| 1. |
- Akhtar, Farid, et al.
(author)
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Aluminophosphate monoliths with high CO2-over-N2 selectivity and CO2 capture capacity
- 2014
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In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:99, s. 55877-55883
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Journal article (peer-reviewed)abstract
- Monoliths of microporous aluminophosphates (AlPO4-17 and AlPO4-53) were structured by binder-free pulsed current processing. Such monoliths could be important for carbon capture from flue gas. The AlPO4-17 and AlPO4-53 monoliths exhibited a tensile strength of 1.0 MPa and a CO2 adsorption capacity of 2.5 mmol g-1 and 1.6 mmol g-1, respectively at 101 kPa and 0°C. Analyses of single component CO2 and N2 adsorption data indicated that the AlPO4-53 monoliths had an extraordinarily high CO2-over-N2 selectivity from a binary gas mixture of 15 mol% CO2 and 85 mol% N2. The estimated CO2 capture capacity of AlPO4-17 and AlPO4-53 monoliths in a typical pressure swing adsorption (PSA) process at 20°C was higher than that of the commonly used zeolite 13X granules. Under cyclic sorption conditions, AlPO4-17 and AlPO4-53 monoliths were regenerated by lowering the pressure of CO2. Regeneration was done without application of heat, which would regenerate them to their full capacity for CO2 adsorption.
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| 2. |
- Anugwom, Ikenna, et al.
(author)
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Switchable ionic liquids (SILs) based on glycerol and acid gases
- 2011
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In: RSC Advances. - : The Royal Society of Chemistry. - 2046-2069. ; 1:3, s. 452-457
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Journal article (peer-reviewed)abstract
- New types of switchable ionic liquids (SILs), containing 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU), glycerol and an acid gas (CO2, SO2), were synthesized and characterized in this study. [DBU][Carbonate] or [sulfonate] were easily synthesized from a non-ionic mixture of molecular organic polyol and amidine base upon bubbling of an acid gas (CO2, SO2). Moreover, they were switched back to the original molecular solvents by flushing out the acid gas (CO2, SO2) by heating and/or bubbling an inert gas such as N2 through it. The structures of the SILs were confirmed by NMR and FTIR. The change from low polarity (molecular solvent) to high polarity (Switchable Ionic Liquid, SIL) was also indicated by the changes in properties, such as viscosity and miscibility with different organic solvents. The decomposition temperatures of the SILs were determined by means of Thermo Gravimetric Analysis (TGA) and gave values in the range of 50 °C and 120 °C for DBU-glycerol-CO2 (SIL1) and DBU-glycerol-SO2 (SIL2), respectively. Due to the reasonable decomposition temperatures, these novel SILs can be employed in multiple applications.
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| 3. |
- Arshadi, Mehrdad
(author)
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Supercritical fluid extraction (SFE) as an effective tool in reducing auto-oxidation of dried pine sawdust for power generation
- 2012
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In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 2, s. 1806-1809
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Journal article (peer-reviewed)abstract
- Supercritical carbon dioxide was an ideal solvent for the extraction of fatty and resin acids from pine sawdust. This green extraction process significantly reduces the potential for uncontrolled autooxidation within this valuable fuel, thereby removing the risk of combustion during storage and processing. Experimental design was utilised to maximize the yield of the extractives. Within the experimental conditions investigated (74–250 bar and 40–60 temperatures gave preferentially high extraction yields, with 97% of the fatty and resin acids in 2 h at 250 bar, 40 sawdust was not significantly affected by the extraction process and the resulting extracts have demonstrated a significant potential for conversion to a biodiesel liquid fuel or higher value chemicals.uC), higher pressures and loweruC, 40 g min21 and with 10% ethanol co-solvent. The calorific value of the pelletized sawdust was not significantly affected by the extraction process and the resulting extracts have demonstrated a significant potential for conversion to a biodiesel liquid fuel or higher value chemicals
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| 4. |
- Bassyouni, Fatma A., et al.
(author)
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Synthesis and biological evaluation of some new triazolo[1,5-a]quinoline derivatives as anticancer and antimicrobial agents
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:46, s. 24131-24141
-
Journal article (peer-reviewed)abstract
- In the present study, versatile multifunctional unreported triazolo[1,5-a]quinoline derivatives were prepared. Compounds 1-19 were synthesized by adopting appropriate synthetic routes and were pharmacologically evaluated for their in vitro anticancer activity against human cancer cell lines: hepatocellular liver carcinoma (HEPG2) and Caucasian breast adenocarcinoma (MCF-7), in addition to their antibacterial and antifungal activities. Compound 4 demonstrated strong inhibitory effects against breast cancer (MCF-7), whereas compounds 8 and 19 exhibited moderate activity against breast carcinoma cell line MCF-7. Compounds 16 and 19 gave moderate activity against liver carcinoma cell line HEPG2. The antimicrobial activity of the prepared compounds was tested against bacteria and fungi. Among them, the results of antimicrobial activity indicated that compounds 4, 9, 11, 13, 15, 17, 18 and 19 were the most active compounds. Compound 4 exhibited strong activity against Fusarium sp., whereas compounds 9, 11, 15, 17, 18 and 19 showed high activity against Escherichia coli. More specifically, compound 17 displayed a high inhibitory effect against Bacillus cereus, Escherichia coli and Rhizoctonia sp.
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| 5. |
- Bermejo Gómez, Antonio, et al.
(author)
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Transition metal-catalyzed redox isomerization of codeine and morphine in water
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 4:74, s. 39519-39522
-
Journal article (peer-reviewed)abstract
- A water-soluble rhodium complex formed from commercially available [Rh(COD)(CH3CN)(2)]BF4 and 1,3,5-triaza-7-phosphaadamantane (PTA) catalyzes the isomerization of both codeine and morphine into hydrocodone and hydromorphone with very high efficiency. The reaction is performed in water, allowing isolation of the final products by simple filtration, which results in very high isolated yields. The reactions can be easily scaled up to 100 g.
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| 6. |
- Bhattacharyya, Anik, et al.
(author)
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A combined experimental and computational study of supramolecular assemblies in ternary copper(II) complexes with a tetradentate N-4 donor Schiff base and halides
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:102, s. 58643-58651
-
Journal article (peer-reviewed)abstract
- Three new copper(II) complexes, [Cu(L)(Cl)]ClO4 (1), [Cu(L)(Br)]ClO4 (2) and [Cu(L)(I)]ClO4 (3), have been prepared from a tetradentate symmetrical Schiff base, N,N'-bis-(1-pyridin-2-yl-ethylidene)-propane-1,3-diamine (L), and characterized by elemental analysis, IR and UV-Vis spectroscopy and single-crystal X-ray diffraction studies. Extended supra-molecular networks were generated through different weak noncovalent forces. Density functional theory (DFT) calculations were employed to estimate the contribution of each interaction in the formation of the assembly using several theoretical models. The interplay between the anion-pi and pi-pi interactions is also analyzed and a mutual reinforcement of both interactions is demonstrated. The assignment of the contribution of each interaction and its mutual influence is certainly important to shed light on the delicate mechanism that governs the molecular recognition and crystal packing.
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| 7. |
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| 8. |
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| 9. |
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| 10. |
- Blomfeldt, Thomas O. J., et al.
(author)
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Novel freeze-dried foams from glutenin- and gliadin-rich fractions
- 2012
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 2:16, s. 6617-6627
-
Journal article (peer-reviewed)abstract
- This is the first study on freeze-dried foams prepared from glutenin- and gliadin-rich fractions of wheat gluten and blends thereof. It was found that the foam density and stiffness could be controlled by a suitable choice of the glutenin/gliadin ratio. The glutenin-rich samples had the highest foam densities and the density decreased with increasing gliadin content. The compression modulus also decreased with increasing gliadin content, which was explained by the decrease in foam density, a more open porosity and the more aggregated/polymerized structure in the presence of glutenin. IR and SE-HPLC revealed that the least aggregated foams were those consisting only of the gliadin-rich fraction. Confocal laser scanning microscopy revealed the presence of both HMW-glutenin and gliadin (to a certain extent probably resisting the ethanol extraction process) in the glutenin-rich foams. SAXS indicated that the gliadin-rich fraction contributed with weakly correlated protein aggregates with a characteristic distance of 40-43 Å.
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| 11. |
- Bodvik, Rasmus, et al.
(author)
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Temperature-dependent adsorption of cellulose ethers on silica and hydrophobized silica immersed in aqueous polymer solution
- 2011
-
In: RSC ADVANCES. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 1:2, s. 305-314
-
Journal article (peer-reviewed)abstract
- The influence of temperature on adsorption and the adsorbed layer properties of methylcellulose (MC) and hydroxypropylmethylcellulose (HPMC) were investigated on silica and hydrophobized silica surfaces immersed in aqueous polymer solution. To achieve a concise understanding a quartz crystal microbalance with dissipation, ellipsometry, and atomic force microscopy imaging were employed. These techniques provide complimentary information on the structure, mass and viscoelastic properties of the polymer layers. Adsorption was first allowed at 25 degrees C. Next, the temperature was increased step-wise up to 50 degrees C and then decreased again. This procedure highlights the temperature dependence of the adsorbed material, as well as the hysteresis in the adsorption due to temperature cycling. A change in temperature not only affects the adsorbed amount, but also the properties of the layer as illustrated by measurements of its water content, thickness and viscoelasticity.
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| 12. |
- Bolognesi, Margherita, et al.
(author)
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2D π-conjugated benzo[1,2-b:4,5-b']dithiophene- and quinoxaline-based copolymers for photovoltaic applications
- 2013
-
In: RSC Advances. - 2046-2069. ; 3:46, s. 24543-24552
-
Journal article (peer-reviewed)abstract
- Two medium gap semiconducting polymers, P(1)-Q-BDT-4TR and P(2)-FQ-BDT-4TR, based on alternate units of alkyl-dithiophene substituted benzodithiophene (BDT) and quinoxaline units (without or with fluorine substitution), are synthesized and fully characterized. The polymers exhibit optical and electrical properties favorable for being employed as donors in BHJ OPV devices, such as: absorption spectra extending up to around 720 nm for a high solar spectrum coverage, deep lying HOMO energy levels for a high device open circuit voltage and LUMO energy levels higher than those of PC61BM and PC71BM for an efficient exciton dissociation. In particular, the presence of alkyl-dithiophene side chains allows us to obtain a high 2D π-conjugation which promotes red shifted absorption profiles, low HOMO energy levels (
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| 13. |
- Boström, Zebastian, 1983, et al.
(author)
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Comparison of Microporous/Mesoporous and Microporous HZSM-5 as Catalyst for Friedel-Crafts Alkylation of Toluene with Ethene
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:54, s. 28786-28793
-
Journal article (peer-reviewed)abstract
- In this work we investigated the effect of mesopores in a standard zeolite used as a catalyst for Friedel-Crafts alkylation of toluene with ethene. A cationic polymer was used for templating mesopores in a microporous ZSM-5 framework. The mesopore-containing zeolite was compared with a regular zeolite with only micropores with respect to conversion, yield and selectivity. The two NaZSM-5 materials were prepared with the same Si/Al molar ratio and diffuse reflection infrared Fourier transform spectroscopy (DRIFT-FTIR) confirmed that the acidity of the ion-exchanged forms (HZSM-5) were identical. Scanning electron microscopy (SEM) and dynamic light scattering (DLS) were used to determine the particle size of the zeolites, which was similar for the two HZSM-5 materials and nitrogen sorption was used to determine the surface area and pore size distribution. X-ray diffraction (XRD) analysis displayed typical crystalline diffraction patterns for the ZSM-5 framework for both the microporous/mesoporous and the microporous ZSM-5 materials. The results from catalytic testing show an increase in the overall conversion of toluene for the zeolite that contains mesopores. Furthermore, a higher product yield (C 9 ) is obtained for this catalyst. The increase in yield and conversion is most likely due to the mesopores; however, incorporation of mesopores in the microporous ZSM-5 framework gives only minor effects on selectivity with respect to mono- vs. dialkylation, and ortho:meta:para ratio. Consequently, this work shows that the presence of mesopores in a microporous ZSM-5 framework is beneficial for the reaction in terms of conversion of starting material and reaction yield but does not markedly affect the product composition. © 2014 the Partner Organisations.
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| 14. |
- Boyd, D. R., et al.
(author)
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Enzyme-catalysed oxidation of 1,2-disulfides to yield chiral thiosulfinate, sulfoxide and cis-dihydrodiol metabolites
- 2014
-
In: Rsc Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:52, s. 27607-27619
-
Journal article (peer-reviewed)abstract
- Enantioenriched and enantiopure thiosulfinates were obtained by asymmetric sulfoxidation of cyclic 1,2-disulfides, using chemical and enzymatic (peroxidase, monooxygenase, dioxygenase) oxidation methods and chiral stationary phase HPLC resolution of racemic thiosulfinates. Enantiomeric excess values, absolute configurations and configurational stabilities of chiral thiosulfinates were determined. Methyl phenyl sulfoxide, benzo[c]thiophene cis-4,5-dihydrodiol and 1,3-dihydrobenzo[c]thiophene derivatives were among unexpected types of metabolites isolated, when acyclic and cyclic 1,2-disulfide were used as substrates for Pseudomonas putida strains. Possible biosynthetic pathways are presented for the production of metabolites from 1,4-dihydrobenzo-2,3-dithiane, including a novel cis-dihydrodiol metabolite that was also derived from benzo[c] thiophene and 1,3-dihydrobenzo[c] thiophene.
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| 15. |
- Bruce, Carl, et al.
(author)
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Well-defined ABA- and BAB-type block copolymers of PDMAEMA and PCL
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:49, s. 25809-25818
-
Journal article (peer-reviewed)abstract
- Triblock copolymers of ABA- and BAB-type consisting of poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA, A) and poly(epsilon-caprolactone) (PCL, B) have successfully been prepared. PDMAEMA-b-PCL-b-PDMAEMA (ABA) and PCL-b-PDMAEMA-b-PCL (BAB) were synthesised by a combination of ring-opening polymerisation of epsilon-CL, atom transfer radical polymerisation of DMAEMA and end-group conversion, performed through either acylation or azide-alkyne "click" chemistry. All samples were analysed by size exclusion chromatography where it was found that the evaluation of PDMAEMA-containing polymers was difficult due to the thermoresponsivity of PDMAEMA, affecting the solubility of the polymer in the temperature range at which the SEC was operated. From differential scanning calorimetry measurements it was shown that the crystallinity could be altered by changing the order of the blocks; with PDMAEMA as the outer block (ABA), the inherent crystallinity of PCL was destroyed while with PCL as the outer block (BAB), the degree of crystallinity was in the same proximity as for a PCL homopolymer.
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| 16. |
- Börjesson, Karl, 1982, et al.
(author)
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Conjugated anthracene dendrimers with monomer-like fluorescence
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:38, s. 19846-19850
-
Journal article (peer-reviewed)abstract
- Two generations of highly emissive conjugated anthracene dendrimers containing up to 9 anthracene units are presented. In these dendrimers, anthracene-like absorption and emission properties are preserved due to the relatively weak electronic coupling between the anthracene units, while evidence of fast crosstalk within the molecular framework is still observed.
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| 17. |
- Cai, Yanling, et al.
(author)
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Photocatalysis induces bioactivity of an organic polymer based material
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:101, s. 57715-57723
-
Journal article (peer-reviewed)abstract
- Several materials, like bioglasses, sintered hydroxyapatite and Ti metals and alloys, have the ability to bond to living bone in vivo, which is a desirable property of biomaterials called bioactivity. In this work, we present a novel strategy to develop bioactivity on the non-bioactive surface of a resin-TiO2 nanocomposite through photocatalysis. The results show that UV irradiation (365 nm, 10 mW cm(-2)) for 8 to 16 h on the resin-TiO2 nanocomposite immersed in water induces bioactivity as indicated by hydroxyapatite growth following immersion of the samples in Dulbecco's phosphate buffered saline for 7 days at 37 degrees C. While a nonirradiated resin-TiO2 surface did not show any hydroxyapatite deposition, a surface after 16 h of UV irradiation was fully covered by hydroxyapatite. In vitro cell adhesion of osteoblast-like MG63 cells confirmed the biocompatibility and bioactivity of the resin-TiO2 surfaces with a hydroxyapatite deposition layer, while the non-irradiated resin-TiO2 surface showed no cell adhesion. Resin-TiO2 nanocomposites, with or without UV irradiation, proved to be nontoxic to two human cell lines, human dermal fibroblasts (hDF) and MG63 cells. It was also shown that an increased dose of UV irradiation decreased bacterial adhesion, which is an additional benefit of the UV treatment and a favourable property for biomedical applications. The combined benefits of biocompatibility, bioactivity, decreased bacterial adhesion and the highly efficient disinfection property of TiO2 photocatalysis under UV light make this resin-TiO2 material an interesting candidate for implant and biomedical device applications.
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| 18. |
- Carlsson, Daniel O., et al.
(author)
-
Cooxidant-free TEMPO-mediated oxidation of highly crystalline nanocellulose in water
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:94, s. 52289-52298
-
Journal article (peer-reviewed)abstract
- Selective oxidation of C6 hydroxyls to carboxyls through 2,2,6,6,-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation, where the oxidizing species (TEMPO+) is generated by cooxidants, such as NaBrO, NaClO or NaClO2, has become a popular way to modify the surfaces of nanocellulose fibrils in aqueous solutions. Employing highly crystalline nanocellulose from Cladophora sp. algae we demonstrate that the same degree of oxidation (D.O.) can be achieved within approximately the same time by replacing the cooxidants with electrogeneration of TEMPO+ in a bulk electrolysis setup. The D.O. is controlled by the oxidation time and the maximum D.O. achieved (D.O. 9.8%, 0.60 mmol g-1 of carboxylic acids and 0 mmol g-1 aldehydes) corresponds to complete oxidation of the surface-confined C6. This shows that TEMPO+ is not sterically hindered from completely oxidizing the fibril surface of Cladophora nanocellulose, in contrast to earlier hypotheses that were based on results with wood-derived nanocellulose. The oxidation does not significantly affect the morphology, the specific surface area (>115 m2 g-1) or the pore characteristics of the water-insoluble fibrous particles that were obtained after drying, but depolymerization corresponding to ∼20% was observed. For extensive oxidation times, the product recovery of water-insoluble fibrils decreased significantly while significant amounts of charge passed through the system. This could indicate that the oxidation proceeds beyond the fibril surface, in contrast to the current view that TEMPO-mediated oxidation is confined only to the surface.
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| 19. |
- Carlsson, Daniel O., et al.
(author)
-
Cooxidant-free TEMPO-mediated oxidation of highly crystalline nanocellulose in water
- 2014
-
In: RSC Advances. - 2046-2069. ; 4:94, s. 52289-52298
-
Journal article (peer-reviewed)abstract
- Selective oxidation of C6 hydroxyls to carboxyls through 2,2,6,6,-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation, where the oxidizing species (TEMPO+) is generated by cooxidants, such as NaBrO, NaClO or NaClO2, has become a popular way to modify the surfaces of nanocellulose fibrils in aqueous solutions. Employing highly crystalline nanocellulose from Cladophora sp. algae we demonstrate that the same degree of oxidation (D.O.) can be achieved within approximately the same time by replacing the cooxidants with electrogeneration of TEMPO+ in a bulk electrolysis setup. The D.O. is controlled by the oxidation time and the maximum D.O. achieved (D.O. 9.8%, 0.60 mmol g-1 of carboxylic acids and 0 mmol g-1 aldehydes) corresponds to complete oxidation of the surface-confined C6. This shows that TEMPO+ is not sterically hindered from completely oxidizing the fibril surface of Cladophora nanocellulose, in contrast to earlier hypotheses that were based on results with wood-derived nanocellulose. The oxidation does not significantly affect the morphology, the specific surface area (>115 m2 g-1) or the pore characteristics of the water-insoluble fibrous particles that were obtained after drying, but depolymerization corresponding to [similar]20% was observed. For extensive oxidation times, the product recovery of water-insoluble fibrils decreased significantly while significant amounts of charge passed through the system. This could indicate that the oxidation proceeds beyond the fibril surface, in contrast to the current view that TEMPO-mediated oxidation is confined only to the surface.
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| 20. |
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| 21. |
- Carlsson, Daniel O., et al.
(author)
-
Tailoring porosities and electrochemical properties of composites composed of microfibrillated cellulose and polypyrrole
- 2014
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In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:17, s. 8489-8497
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Journal article (peer-reviewed)abstract
- Composites of polypyrrole and nanocellulose (PPy/nanocellulose) have a high potential as electrodes in energy-storage devices and as membranes for electrochemically controlled ion-exchange systems. In the present work, it is demonstrated that such composites with 42-72% porosity can be produced by using microfibrillated cellulose (MFC) prepared through enzymatic pretreatment or carboxymethylation, or by using different amounts of MFC in the composite synthesis. Together with previous work, this shows that the porosity of PPy/nanocellulose composites can be tailored from 30 to 98% with increments of similar to 10%. Employing the full porosity range of the composites, it is demonstrated that the electrochemical oxidation rate of the materials depends on their porosity due to limitations in the counter ion diffusion process. By tailoring the porosities of PPy/nanocellulose composites, the electrochemical properties can consequently be controlled. The latter provides new possibilities for the manufacturing of electrochemically controlled ion-extraction and energy storage devices with optimized volumetric energy and power densities.
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| 22. |
- Carrick, Christopher, et al.
(author)
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Hollow cellulose capsules from CO2 saturated cellulose solutions - Their preparation and characterization
- 2013
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 3:7, s. 2462-2469
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Journal article (peer-reviewed)abstract
- A new material consisting of mm-sized hollow cellulose spheres, for biomedical applications or for the preparation of low weight porous materials has been prepared by a unique solution precipitation (SP) method. The technique is based on three separate steps. In the first step, high molecular mass, non-modified cellulose is dissolved in a suitable solvent. This cellulose solution is then saturated with a suitable gas (CO2 or N2 in the present work) and finally this gas-saturated solution is drop-wise added to a water reservoir. In this step, the cellulose is precipitated and a gas bubble is nucleated in the center of the cellulose sphere. When stored in water, the hollow center is filled with water, indicating that the capsule wall is porous in nature. This was also supported by BET-area measurements as well as by high resolution SEM-images of broken capsule walls. The internal void volume of a capsule was about 5 μl and the wall volume was about 8 μl. It was also established that the properties of the cellulose capsules, i.e. wall and void volume, the specific surface area, the average pore size of the capsule wall, the wall density, and the compressive load capacity could be tuned by the choice of cellulose concentration in the solution before precipitation. The capsule wall volume and void volume were also affected by the choice of gas, the gas pressure and the gas dissolution time during the gas saturation step. The response of the cellulose wall of the prepared capsules to changes in pH and ion concentration in the surrounding solution was also investigated. The swelling-shrinking behavior was further investigated by introducing more charges to the capsule wall, via carboxymethylation of the cellulose. This was achieved by using carboxymethylated cellulose which increased the swelling-shrinking effect. The results show a typical polyelectrolyte gel behavior of the capsule wall and the wet modulus of the cellulose wall was determined to be between 0.09-0.2 MPa depending on the charge of the cellulose in the capsule wall. Furthermore, the freeze dried cellulose spheres had a modulus of 1.9-7.4 MPa, depending on the cellulose concentration during the preparation of the spheres. These cellulose capsules are suitable both for the preparation of porous materials, where these larger spheres are joined together in 3D-shaped materials, and for controlled release where the interior of the capsules is filled with active substances and these substances are released by controlling the pores in the capsule walls.
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| 23. |
- Carrick, Christopher, et al.
(author)
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Native and functionalized micrometre-sized cellulose capsules prepared by microfluidic flow focusing
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:37, s. 19061-19067
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Journal article (peer-reviewed)abstract
- Cellulose capsules with average outer and inner radii of approximately 44 mu m and 29 mm respectively were prepared from cellulose dissolved in a mixture of lithium chloride and dimethylacetamide using a microfluidic flow focusing device (MFFD). The MFFD had three inlets where octane oil in a cellulose solution in silicone oil was used to produce a double emulsion containing a cellulose capsule. This technique enables the formation of capsules with a narrow size distribution which can be beneficial for drug delivery or controlled release capsules. In this respect, cellulose is a highly interesting material since it is known to cause no autoimmune reactions when used in contact with human tissue. Furthermore, by controlling the chemical properties of the cellulose, it is possible to trigger a swelling of the capsules and consequentially the release of an encapsulated substance, e. g. a model drug, when the capsule becomes exposed to an external stimulus. To demonstrate this, capsules were functionalized by carboxymethylation to be pH- responsive and to expand approximately 10% when subjected to a change in pH from 3 to 10. The diffusion constant of a model drug, a 4 kDa fluorescently labelled dextran, through the native capsule wall was estimated to be 6.5 X 10(-14) m(2) s(-1) by fitting fluorescence intensity data to Fick's second law.
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| 24. |
- Chadwick, Edward G., et al.
(author)
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Compositional characterisation of metallurgical grade silicon and porous silicon nanosponge particles
- 2013
-
In: RSC Advances. - 2046-2069. ; 3:42, s. 19393-19402
-
Journal article (peer-reviewed)abstract
- Porous silicon is generally achieved through electro-chemical etching or chemical etching of bulk silicon in hydrofluoric acid based solutions. The work presented here explores the effect of a chemical etching process on a metallurgical grade silicon powder. It is found that the metallurgical grade silicon particles contain surface bound impurities that induce a porous structure formation upon reaction with the chemical etchant applied. The correlation between the resultant porous structure formed due to the material composition is examined in detail. The elemental composition is determined using a combination of X-ray Photoelectron Spectroscopy and Time of Flight Secondary Ion Mass Spectroscopy. The porous structure is analysed using Transmission Electron Microscopy and Scanning Electron Microscopy. Three samples of the silicon particles analysed for this study include an un-etched bulk silicon powder sample and two samples of chemically etched powder. Pore formation within the particles is found to be dependent on the presence, dispersion, and local concentration of surface bound impurities within the starting powder.
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| 25. |
- Chen, Bin, et al.
(author)
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A novel trigeminal zinc porphyrin and corresponding porphyrin monomers for dye-sensitized solar cells
- 2014
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In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:21, s. 10439-10449
-
Journal article (peer-reviewed)abstract
- A novel trigeminal zinc porphyrin sensitizer (T) and two zinc porphyrin monomers (M1 and M2) were successfully designed and synthesized. The spectral, electrochemical, and photovoltaic properties of the porphyrin dyes were investigated. Compared with M1, the molecule of M2 has an additional aliphatic n-hexyloxyl chain at the meso-position of the porphyrin framework, and such a structure is favorable for the formation of a compact hydrophobic layer at the TiO2 surface and the retardation of the diffusion of I-3(-) ions into the nanoporous TiO2 electrode, resulting in more effective suppression of the charge recombination process and a higher V-oc. Meanwhile, M2 has larger IPCE values than those of M1, leading to the higher J(sc) value. Thus, the DSSC devices based on M2 demonstrated a relatively high power conversion efficiency of 5.77%, with the J(sc), V-oc and ff values of 13.93 mA cm(-2), 732 mV, and 0.566, respectively. Even though dye T has the highest molar absorption coefficients and multiple binding moieties, the corresponding power conversion efficiency is 2.30%, which is lower than those for M1 and M2. These observations may be ascribed to the low efficiency of the electron injection process caused by the isolation of the LUMOs from the anchoring carboxyl groups in addition to the lowest adsorption amount.
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| 26. |
- Chen, Cheng, et al.
(author)
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Highly efficient organic dyes containing a benzopyran ring as a pi-bridge for DSSCs
- 2013
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 3:31, s. 12688-12693
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Journal article (peer-reviewed)abstract
- A series of novel organic dyes containing a benzopyran ring as a p-bridge have been designed and applied in dye-sensitized solar cells (DSSCs). This series of dyes show the excellent DSSCs' performance, due to their efficient light-to-photocurrent conversion in the region from 380 nm to 600 nm, with the highest IPCE values exceeding 90%. Through modification of the donor units, an efficiency as high as 7.5% has been achieved under standard light illumination (AM 1.5G, 100 mW cm(-2)) by the dye CC103.
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| 27. |
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| 28. |
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| 29. |
- Cheung, Ocean, et al.
(author)
-
Zeolites and related sorbents with narrow pores for CO2 separation from flue gas
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:28, s. 14480-14494
-
Research review (peer-reviewed)abstract
- Adsorbents with small pores are especially relevant for capturing carbon dioxide at large emission sources. Such sorbents could be used potentially to reduce the energy demands for separating carbon dioxide from flue gas as compared with today's technologies. Here, we review the literature for crystalline, inorganic, and potentially inexpensive adsorbents. A number of different adsorbents with narrow pore openings are compared.
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| 30. |
- Claudino, Mauro, et al.
(author)
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Thiol-ene coupling kinetics of D-limonene : a versatile 'non-click' free-radical reaction involving a natural terpene
- 2013
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In: RSC Advances. - : RSC Publishing. - 2046-2069. ; 3:27, s. 11021-11034
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Journal article (peer-reviewed)abstract
- The free-radical photoinduced thiol-ene reaction between D-limonene, as renewable diolefinic substrate, and two mono-/tri-functional thiols (iso-tridecyl 3-mercaptopropionate and trimethylolpropane tris(3-mercaptopropionate)), has been investigated kinetically to define a relationship between alkene structure and reactivity. Separate thiol-ene solutions of the appropriate thiol in d-chloroform, supplemented with 1.0 wt% of DMPA (Irgacure 651), were subjected to polychromatic UV-irradiation and the chemical changes monitored discontinuously via H-1 NMR spectroscopy to quantify double bond conversion. The kinetic concentration profiles were modeled analytically and simulated in the application software COPASI for parameter estimation and to verify if the experimental data explained a suggested mechanistic scheme. Empirical results demonstrate that the external vinylidene bond of limonene reacts about 6.5 times faster with thiol than the internal trisubstituted 1-methyl-cyclohexene unsaturation. The selectivity observed for the two unsaturations was successfully explained by means of a simplified steady-state equation derived from the sequential reaction mechanism accounting for propagation and chain-transfer elementary steps with estimated rate coefficients. Kinetic modeling results attribute the difference in selectivity partially to steric impediments controlling thiyl-radical insertion onto the double bonds and predominantly to differences in relative energy between the two tertiary insertion carbon radical intermediates. The rate-limiting step was identified as the third chain-transfer hydrogen-abstraction reaction promoted by the second insertion carbon radical intermediate. High thiol-ene conversions were obtained in a timely fashion without major influence of secondary reactions demonstrating the suitability of this reaction for network forming purposes. The mechanistic and kinetic information collected can be used as a quantitative predictive tool to assess the potential use of D-limonene in thiol-ene network forming systems involving multifunctional alkyl ester 3-mercaptopropionates.
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| 31. |
- Claudino, Mauro, et al.
(author)
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Utilizing thiol-ene coupling kinetics in the design of renewable thermoset resins based on D-limonene and polyfunctional thiols
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:20, s. 10317-10329
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Journal article (peer-reviewed)abstract
- An extended model is developed to predict the free-radical thiol-ene reaction dynamics between D-limonene, as a renewable diolefin, and a monothiol compound (iso-tridecyl 3-mercaptopropionate) in bulk liquid conditions. Thermally and photo-initiated reactions of the two monomers showed favored thiol-ene coupling at the exo-isopropenyl alkene structure when reacted at 1 : 1 and 1 : 0.5 mole ratios. Experimental kinetic data obtained from the two stoichiometries were well reproduced numerically via the simulation software COPASI by introducing a multi-route mechanistic scheme with propagation-chain-transfer steps accounting for primary (mono-additions) and secondary (di-addition) modes of coupling. The differences in intrinsic double-bond reactivity enable synthesis of limonene-terminated resins (mono-versus poly-disperse) as multifunctional network precursors. Off-stoichiometry manipulations in the initial mole ratio, assisted by numerical simulations, offer a convenient approach to visualize the overall reaction system kinetics irrespective of temporal effects, thus being regarded as an important guiding tool for chemists aiming at designing thiol-ene systems based on limonene.
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| 32. |
- Cong, Jiayan, et al.
(author)
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A highly efficient colourless sulfur/iodide-based hybrid electrolyte for dye-sensitized solar cells
- 2012
-
In: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 2:9, s. 3625-3629
-
Journal article (peer-reviewed)abstract
- A new kind of hybrid electrolyte with S2-/S-x(2-) and I- was invented, and the new hybrid system was demonstrated to outperform the well-known I-/I-3(-) redox system in DSCs. An efficiency of 9.1% was achieved in our lab under AM 1.5 illumination using the dye N719, considerably higher than the efficiency of 8.0% of the I-/I-3(-)-based electrolyte.
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| 33. |
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| 34. |
- Delhorme, Maxime, et al.
(author)
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Gel, glass and nematic states of plate-like particle suspensions: charge anisotropy and size effects
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:66, s. 34793-34800
-
Journal article (peer-reviewed)abstract
- The influence of the charge anisotropy and platelet size on the formation of gel and glass states and nematic phases in suspensions of plate-like particles is investigated using Monte Carlo simulations in the canonical ensemble. The platelets are modeled as discs with charged sites distributed on a hexagonal lattice. The edge sites can carry a positive charge, while the remaining sites are negatively charged giving rise to a charge anisotropy. A screened Coulomb potential plus a short range repulsive potential are used to describe the interactions between the sites of the platelets. The liquid-gel transition is found to be favored by a high charge anisotropy and by large particles. Oppositely, the liquid-glass transition is favored for small particles without charge anisotropy, i.e., fully negatively charged. Finally, we find that the isotropic/nematic transition is disfavored by the charge anisotropy. For a strong charge anisotropy, the nematic phase does not form and, instead, a gel/columnar transition is found.
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| 35. |
- Dom, R., et al.
(author)
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Eco-friendly ferrite nanocomposite photoelectrode for improved solar hydrogen generation
- 2013
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In: RSC Advances. - 2046-2069. ; 3:35, s. 15217-15224
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Journal article (peer-reviewed)abstract
- For the first time, a ferrite nanocomposite photoelectrode (FNCP) has been fabricated and investigated for photoelectrochemical hydrogen production from water under simulated solar light. The ZnFe2O4:Fe 2O3 nanocomposite photoanode has been fabricated via a single step methodology using a novel approach involving the solution precursor plasma spraying technique. The FNCP is achieved by optimal phase formation during the deposition of the ferrite film (∼10 μm) over a stainless steel substrate. It exhibits an enhanced photoactivity 6 times higher compared to pure ZnFe2O4 (ZFO), under simulated-solar (AM1.5 G) illumination. Its Mott-Schottky characterization reveals an n-type semiconducting behaviour, indicating an order of magnitude higher donor density (Nd ∼ 1017 cm-3) than the pure phase ZnFe2O4 electrode. It also exhibits a low band gap of 1.94 eV demonstrating that it can more efficiently absorb visible light photons than other systems comprising of bare zinc ferrite or iron oxide. The FNCP yielded a solar-to-hydrogen conversion efficiency of 1.25% under simulated solar radiation (AM1.5 G) with a hydrogen evolution rate of 99 μmol h-1. Electrochemical impedance spectroscopy of the FNCP revealed a significantly improved charge transfer characteristic compared to ZnFe2O 4. An enhanced photoactivity for the oxidation of water from the FNCP is attributed to its improved optical absorption and better charge transfer properties induced by the existence of Fe2O3 in ZnFe 2O4. © The Royal Society of Chemistry 2013.
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| 36. |
- Endrodi, Balazs, et al.
(author)
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Reasons behind the improved thermoelectric properties of poly(3-hexylthiophene) nanofiber networks
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 4:98, s. 55328-55333
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Journal article (peer-reviewed)abstract
- Enhanced thermoelectric properties of poly(3-hexylthiophene) nanofiber networks, doped in their reaction with silver cations, are presented. The role of charge carrier concentration and mobility (influenced by the supramolecular structure and nanoscale morphology) is discussed. The nanonet structure leads to a six fold increase in the ZT value compared to the bulk polymer counterpart.
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| 37. |
- Fang, Changfeng, et al.
(author)
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Computational study of the working mechanism and rate acceleration of overcrowded alkene-based light-driven rotary molecular motors
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 4:20, s. 10240-10251
-
Journal article (peer-reviewed)abstract
- In recent years, much progress has been made in the design, synthesis and operation of light-driven rotary molecular motors based on chiral overcrowded alkenes. Through consecutive cis–trans photoisomerization and thermal helix inversion steps, where the latter dictate the overall rate of rotation, these motors achieve a full 360° unidirectional rotation around the carbon–carbon double bond connecting the two (rotator and stator) alkene halves. In this work, we report quantum chemical calculations indicating that a particularly fast-rotating overcrowded alkene-based motor capable of reaching the MHz regime, can be made to rotate even faster by the substitution of a rotator methyl group with a methoxy group. Specifically, using density functional theory methods that reproduce the rate-limiting 35 kJ mol−1 thermal free-energy barriers shown by the methyl-bearing motor with errors of 5 kJ mol−1 only, it is predicted that this substitution reduces these barriers by a significant 15–20 kJ mol−1. This prediction is preceded by a series of benchmark calculations for assessing how well density functional theory methods account for available experimental data (crystallographic, UV-vis absorption, thermodynamic) on the rotary cycles of overcrowded alkenes, and a detailed examination of the thermal and photochemical reaction mechanisms of the original motor of this type.
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| 38. |
- Fang, Mei, et al.
(author)
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Particle-free inkjet printing of nanostructured porous indium tin oxide thin films
- 2013
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 3:42, s. 19501-19507
-
Journal article (peer-reviewed)abstract
- We report a simple, low-cost, single-step inkjet printing method for the fabrication of nanostructured, highly transparent and conductive ITO films, which completely avoids the use of ITO particles in the fabrication process. In our method, the inks are formed from a liquid solution presenting a properly selected mixture of indium and tin acetates. After jet printing, the ink is decomposed during a subsequent annealing step, in which the released CO2 gas bubbles control the ITO nucleation process to provide a porous film texture. We show that the fabricated ITO films are highly crystalline, stoichiometric, and nanoporous with controlled porosity. Electrical measurements show relatively low resistivity values for the films (down to 0.029 Omega cm) comparable to those of the best ITO thin films fabricated by other methods. Optical ellipsometry tests demonstrate a relatively high refractive index (1.5-1.7) and high transparency of the films over a wide region of the spectrum ranging from 500 to 1700 nm. Since the method does not require any pre-fabricated ITO particles, masks or templates, and enables the deposition of films on substrates of various materials and shapes, it can be employed for fabrication of nanoporous ITO films for a diversity of applications, including solar cell, bio- and chemical sensing, etc.
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| 39. |
- Feifel, Sven C., et al.
(author)
-
Electrocatalytically active multi-protein assemblies using nanoscaled building blocks
- 2013
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 3:10, s. 3428-3437
-
Journal article (peer-reviewed)abstract
- Biosensors based on nanomaterials constitute an emerging area of interdisciplinary research. In particular in electrochemical sensors, electron transfer cascades can be used for defined signal generation. Our study describes the investigation of silica nanoparticles (SiNPs), DNA, cytochrome c (cyt c) and cellobiose dehydrogenase (CDH) for the development of catalytically active multi-protein assemblies. We report on direct and interprotein electron transfer reaction cascades of CDH and cyt c in an immobilized form by means of nanoscaled building blocks: Carboxy-modified SiNPs, and DNA. The building blocks provide an artificial matrix, which permit protein arrangement in an electro- and catalytically-active form. Multilayered protein architectures on electrodes featuring direct and interprotein electron transfer by the use of entirely different nanoscaled building blocks has been established for the first time. In addition we highlight, that the secondary building blocks (DNA or SiNPs) used for the construction as well as the glycosylation of the enzyme (CDH) play a key role for the mode of operation in such complex entities.
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| 40. |
- Galstyan, V., et al.
(author)
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TiO 2 nanotubular and nanoporous arrays by electrochemical anodization on different substrates
- 2011
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 1:6, s. 1038-1044
-
Journal article (peer-reviewed)abstract
- The preparation of nanotubular arrays on different substrates and nanoporous structures on titanium foil by means of electrochemical anodization of titanium layer has been investigated. Highly aligned nanotubes of TiO 2 on flexible, rough and flat substrates are reported. Modification of anodization conditions of titanium on specific substrates such as polyethylene terephthalate (PET), conducting glass and granular alumina was found to affect the morphology of TiO 2 nanotubes. Two different kinds of aqueous electrolytes have been applied, containing either glycerol or H 2SO 4, in order to investigate the effect of ion mobility on anodization process. Galvanostatic and potentiostatic anodization modes have been investigated: transition from nanotubes to nanoporous structures has been highlighted in galvanostatic mode, depending on the intensity of anodization current density. These results pave the way for massive production of TiO 2 nanotubes over, in principle, whatever substrate, enabling exploitation of new functional properties derived from the combination of tubes and substrates. This journal is © The Royal Society of Chemistry 2011.
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| 41. |
- Golda-Cepa, M., et al.
(author)
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LDI-MS examination of oxygen plasma modified polymer for designing tailored implant biointerfaces
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:50, s. 26240-26243
-
Journal article (peer-reviewed)abstract
- A versatile polymer coating for biomaterials was fabricated by the mild oxygen plasma treatment of Chemical Vapour Deposited (CVD) parylene C. The surface properties were tailored while the excellent protective properties of the bulk were preserved. The species, formed due to the plasma functionalisation, were fingerprinted by a novel Laser Desorption/Ionisation-Mass Spectrometry (LDI-MS) method. Improved osteosarcoma cells (line MG-63) attachment and viability on a modified surface were demonstrated.
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| 42. |
- Gonzalez-Posada, Fernando, 1980, et al.
(author)
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Oxidation of copper nanoparticles in water monitored in situ by localized surface plasmon resonance spectroscopy
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:40, s. 20659-20664
-
Journal article (peer-reviewed)abstract
- Disc-shaped copper nanoparticles (Cu NPs) were fabricated by hole-mask colloidal lithography on bare and thin titania film covered fused silica substrates. The dynamics of Cu oxide formation around the NPs were studied in water by localized surface plasmon resonance (LSPR) spectroscopy. We found that the oxidation rate is strongly enhanced under UV irradiation when the NPs are on the surface of the titania film, in comparison to NPs deposited on an inert fused silica substrate. The reason is sought in the ability of TiO2 to create hydroxyl radicals with strong oxidative potential in water under UV irradiation and the charge transfer at the interface between the Cu NPs and the TiO2. The post irradiation analysis of the samples with X-ray photoelectron spectroscopy provides complementary evidence for Cu oxide formation. In addition, size and shape changes of the NPs, as measured by atomic force microscopy and scanning electron microscopy, indicate (photo) corrosion of the NPs. Our results demonstrate the potential of using LSPR spectroscopy to monitor the oxidation of Cu NPs in situ and in different environments.
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| 43. |
- Gustavsson, Sanna, et al.
(author)
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Polarization transfer solid-state NMR: a new method for studying cellulose dissolution
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:60, s. 31836-31839
-
Journal article (peer-reviewed)abstract
- Polarization transfer solid-state NMR is shown to give molecular-level information about both dissolved and solid cellulose in aqueous dissolution media with sodium hydroxide or tetrabutylammonium hydroxide, thus paving the way for future studies of the molecular details of cellulose dissolution.
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| 44. |
- Hao, Yan, et al.
(author)
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Photo-induced electron transfer study of D-pi-A sensitizers with different type of anchoring groups for dye-sensitized solar cells
- 2012
-
In: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 2:14, s. 6011-6017
-
Journal article (peer-reviewed)abstract
- A new D-pi-A organic dye HY102 with a lateral anchoring group and two reference dyes HY102-1 (using cyanoacrylic acid as an electron acceptor and the anchoring group) and HY102-2 (containing both cyanoacrylic acid and lateral carboxylic acid) have been synthesized. The optical and electrochemical test results from the three different styles of photosensitizers show that the excited electrons of the novel dye HY102 with lateral carboxylic acid group most probably are injected into the CB of TiO2 through the electron acceptor moiety close to the TiO2 surface by spatial transfer, not through the lateral anchoring group of the carboxylic acid. Research into the photo-induced electron transfer of the novel sensitizers with lateral anchoring system is reasonable and crucial for further improving efficiencies by modifying the molecular structures.
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| 45. |
- Hellsing, Maja S., et al.
(author)
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Structure of a large colloidal crystal : controlling orientation and three-dimensional order
- 2012
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 2:18, s. 7091-7098
-
Journal article (peer-reviewed)abstract
- The three-dimensional crystal structure of charge stabilised polystyrene latex in deionised water was investigated by small-angle neutron diffraction. Crystallisation with a grain size of approximately 1 x 1 cm(2) was observed when the sample was flowed gently in to a 2 mm path cell. Bragg scattering peaks arising from the structure were observed under rotation about three perpendicular axes of the sample. The diffraction patterns indicate clearly that there is a cubic close packed structure with a 110 axis perpendicular to the cell wall. Rotations in small steps show large changes and indicate that the crystal is well oriented and has three-dimensional order. The crystal orientation was controlled by the meniscus and direction of flow when filling the cell.
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| 46. |
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| 47. |
- Hong, Tao, et al.
(author)
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Syntheses of mono- and diacylated bipyrroles with rich substitution modes and development of a prodigiosin derivative as a fluorescent Zn(II) probe
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:12, s. 6133-6140
-
Journal article (peer-reviewed)abstract
- The acylation of 2,20-bipyrrole with pentafluorobenzoyl chloride in the presence of AlCl3 afforded six acylated products with rich alpha-, beta-, beta(1)-, alpha,alpha'-, alpha,beta(')-, and alpha,beta(1)'-substitution modes for 1-6, respectively. Then, the alpha,alpha'-diacylated compound 4 was used to synthesize a prodigiosin derivative 9, which provides an alternative method for the syntheses of prodigiosin derivatives. Crystal structures of 1, 4 and 9 show interesting supramolecular dimers formed by multiple hydrogen bonds, O...pi interactions, as well as pi... pi interactions. Interestingly, 9 shows fluorescence turn-on probing behavior towards Zn2+ both in DMF and in DMF-HEPES, with high sensitivity and selectivity. The detection limit for Zn2+ in DMF was calculated to be 1.1 x 10(-8) M.
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| 48. |
- Hu, Guangzhi, et al.
(author)
-
Reduction free room temperature synthesis of a durable and efficient Pd/ordered mesoporous carbon composite electrocatalyst for alkaline direct alcohols fuel cell
- 2014
-
In: RSC Advances. - : RSC Publishing. - 2046-2069. ; 4:2, s. 676-682
-
Journal article (peer-reviewed)abstract
- The development of easy and environmentally benign synthesis methods of efficient electrocatalysts for use in energy conversion applications motivates researchers all over the world. Here we report a novel and versatile method to synthesize well-dispersed palladium-functionalized ordered mesoporous carbons (Pd/OMCs) at room temperature without any reducing agent by one-pot mixing of tri(dibenzylideneacetone)palladium(0) (Pd2DBA3) and OMCs together in a common N,N-dimethylformamide (DMF) solution. The formation of Pd nanoparticles and their crystallization on the OMC is catalyzed by protons in the solution and can thus be controlled by the solution pH. The complete process and the as-prepared nanocomposite was characterized by UV-spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (HTEM), X-ray photoelectron spectrum (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The electrocatalytic property of the as-decorated material was examined with cyclic voltammetry (CV). The Pd/OMC composite shows up to two times higher electrocatalytic ability with a significantly better durability towards ethanol and methanol oxidation in alkaline media compared to commercial high surface area conductive carbon black Vulcan XC-72 decorated with equivalent Pd nanoparticles. Our described method provides new insight for the development of highly efficient carbon based nanocatalysts by simple and environmentally sound methods.
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| 49. |
- Hu, G. Z., et al.
(author)
-
Reduction free room temperature synthesis of a durable and efficient Pd/ordered mesoporous carbon composite electrocatalyst for alkaline direct alcohols fuel cell
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:2, s. 676-682
-
Journal article (peer-reviewed)abstract
- The development of easy and environmentally benign synthesis methods of efficient electrocatalysts for use in energy conversion applications motivates researchers all over the world. Here we report a novel and versatile method to synthesize well-dispersed palladium-functionalized ordered mesoporous carbons (Pd-OMCs) at room temperature without any reducing agent by one-pot mixing of tri(dibenzylideneacetone) palladium(0) (Pd(2)DBA(3)) and OMCs together in a common N,N-dimethylformamide (DMF) solution. The formation of Pd nanoparticles and their crystallization on the OMC is catalyzed by protons in the solution and can thus be controlled by the solution pH. The complete process and the as-prepared nanocomposite was characterized by UV-spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectrum (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The electrocatalytic property of the decorated material was examined with cyclic voltammetry (CV). The Pd-OMC composite shows up to two times higher electrocatalytic ability with a significantly better durability towards ethanol and methanol oxidation in alkaline media compared to commercial high surface area conductive carbon black Vulcan XC-72 decorated with equivalent Pd nanoparticles. Our described method provides new insight for the development of highly efficient carbon based nanocatalysts by simple and environmentally sound methods.
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| 50. |
- Hua, Kai, et al.
(author)
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Translational study between structure and biological response of nanocellulose from wood and green algae
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:6, s. 2892-2903
-
Journal article (peer-reviewed)abstract
- The influence of nanostructure on the cytocompatibility of cellulose films is analyzed providing insight into how physicochemical properties of surface modified microfibrillated cellulose (MFC) and Cladophora nanocellulose (CC) affect the materials cytocompatibility. CC is modified through TEMPO-mediated oxidation and glycidyltrimethylammonium chloride (EPTMAC) condensation to obtain anionic and cationic nanocellulose samples respectively, while anionic and cationic MFC samples are obtained by carboxymethylation and EPTMAC condensation respectively. Films of unmodified, anionic and cationic MFC and CC are prepared by vacuum filtration and characterized in terms of specific surface area, pore size distribution, degree of crystallinity, surface charge and water content. Human dermal fibroblasts are exposed to culture medium extracts of the films in an indirect contact cytotoxicity test. Moreover, cell adhesion and viability are evaluated in a direct contact assay and the effects of the physicochemical properties on cell behavior are discussed. In the indirect cytotoxicity test no toxic leachables are detected, evidencing that the CC and MFC materials are non-cytotoxic, independently of the chemical treatment that they have been subjected to. The direct contact tests show that carboxymethylated-MFC presents a more cytocompatible profile than unmodified and trimethylammonium-MFC. TEMPO-CC promotes fibroblast adhesion and presents cell viability comparable to the results obtained with the tissue culture material Thermanox. We hypothesize that the distinct aligned nanofiber structure present in the TEMPO-CC films is responsible for the improved cell adhesion. Thus, by controlling the surface properties of cellulose nanofibers, such as chemistry, charge, and orientation, cell adhesion properties can be promoted.
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