| 1. |
- Lan, Xiaoyu, et al.
(författare)
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Self-Assembly of Diblock Copolymers Containing Thermo- and Photoresponsive Lower Critical Solution Temperature Phase Behavior Polymer with Tunable Assembly Temperature in an Ionic Liquid Mixture
- 2019
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Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 4:6, s. 11229-11236
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Tidskriftsartikel (refereegranskat)abstract
- This work prepared a type of diblock copolymer with thermo- and photosensitivity in ionic liquids (ILs). P(N,N-dimethylacrylamide) (compatible with ILs) was prepared as one segment, while butyl acrylate (BA) and 4-phenylazophenylmethacrylate (AzoMA) were copolymerized as another segment P(AzoMA-r-BA) with stimuli responsiveness. The diblock copolymer showed tunable lower critical micellization temperature (LCMT) in two mixed imidazole ionic liquids. The value of LCMT depends on not only the conformation status of the azo group in copolymers but also the azo group content in copolymers and mixed ratio of ionic liquids. Based on this tunable LCMT, photoinduced micellization/demicellization can be achieved near room temperature by alternate irradiation with visible and ultraviolet light, and it is totally reversible.
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| 2. |
- Ma, Xiaofeng, et al.
(författare)
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Photo-induced Actuator using Temperature and Light Dual Responsive Azobenzene Containing Ion Gel in Ionic Liquid
- 2020
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Ingår i: European Polymer Journal. - : Elsevier. - 0014-3057 .- 1873-1945. ; 123
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Tidskriftsartikel (refereegranskat)abstract
- A series of well-defined random copolymers comprising butyl acrylate (BA) and 4-phenylazophenylmethacrylate (AzoMA) (P(AzoMA-r-BA)) are prepared successfully by reversible addition fragmentation chain transfer (RAFT) polymerization. P(AzoMA-r-BA)s show LCST-type phase transition in 1-butyl-3-methylimidazolium bis(trifluoromethanesulfone)amide ([C4mim][NTf2]). LCST depends on the photoisomerization state of azobenzene, as well as on the AzoMA composition in the random copolymers. LCST of (P(cis-AzoMA-r-BA) is significantly higher than that of P(trans-AzoMA-r-BA), because cis-AzoMA and trans-AzoMA behave as solvato-philic and solvato-phobic comonomer, respectively. At a bistable temperature, photo-induced phase separation is completely reversible. Secondly, based on this phenomenon, a thermo- / photo- responsive ion gel (BA-AzoMA ion gel) can be prepared by free radical polymerization of BA and AzoMA using ethylene glycol dimethacrylate (EGDMA) as crosslinker in [C4mim][NTf2]. BA-AzoMA ion gel shows high temperature contraction and low temperature expansion behavior, due to LCST-type phase behavior of polymer system consisting of AzoMA and BA. Contraction temperature of BA-AzoMA ion gel depends on photoisomerization state of the azobenzene group in polymers. At a bistable temperature, photo-induced expansion-contraction is reversible. Finally, a Photo-induced actuator can be realized using BA-AzoMA ion gel at suitable temperatures, featuring reversible bending by alternate irradiating with visible and UV light. The bending behavior is also demonstrated.
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| 3. |
- Wang, Lei, et al.
(författare)
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Coumarin derivative trigger controlled photo-healing of ion gels and photo-controlled reversible adhesiveness
- 2021
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Ingår i: European Polymer Journal. - : Elsevier. - 0014-3057 .- 1873-1945. ; 144
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Tidskriftsartikel (refereegranskat)abstract
- Fabrication strategies for photo-responsive ion gels have attracted attention owing to their precise spatial and temporal control with predetermined responses to light stimuli. In this work, a reversible light-driven method was introduced to devise photo-responsive ion gels by harnessing coumarin-based building blocks under 365 nm irradiation. A series of random copolymers composed of N, N-dimethylacrylamide (DMA) and 7-(2′-methacryloyloxyethoxy)–4-methylcoumarin (MAOEMC), namely P(DMA-r-MAOEMC), were synthesized through reversible addition-fragmentation chain transfer (RAFT) polymerization with sufficient molecular weight (≈100 kDa). The coumarin moieties in those polymers exhibited a reversible photo-induced dimerization and photocleavage behavior in 1-ethyl-3-methylimidazolium bis (trifluoromethylsufonyl) imide ([C2mim][NTf2]). Those polymers - ionic liquid system at high polymer concentration (20 wt%) under suitable wavelength UV light irradiation led to sol–gel transition, which could be functionalized as photo-healable material and photo-controlled adhesion agents. Notably, the photo-controlled adhesiveness was reversible and can be mediated from 1.2 MPa to 0.2 MPa. This work opens new avenues to develop multifunctional ion gels using dynamic covalent bonds.
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| 4. |
- Wang, Lei, et al.
(författare)
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Photo-healable ion gel with high mechanical property, fatigue resistance and shear resistance using a coumarin group containing diblock copolymer in an ionic liquid
- 2022
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Ingår i: European Polymer Journal. - : Elsevier. - 0014-3057 .- 1873-1945. ; 165
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Tidskriftsartikel (refereegranskat)abstract
- Ion gels, polymer networks swollen with ionic liquid (IL), are ideal materials for application in flexible electronic devices. It remains a challenge to fabricate an ion gel with photo-healing, high mechanical properties, fatigue resistance and shear resistance. Herein, a well-defined diblock copolymer polystyrene-b-poly(methyl acrylate-r-7-(2′-methacryloyloyloxyethoxy)-4-methylcoumarin) (PS-b-P(DMA-r-MAOEMC), brief name: SMM, PS: IL-phobic segment and P(DMA-r-MAOEMC): IL-philic segment) was synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization. For comparison, a random copolymer P(DMA-r-MAOEMC) (MM) also be prepared. In dilute solution, the SMM can form spherical micelles with PS-core surrounded by P(DMA-r-MAOEMC) corona chains in an IL, 1-ethyl-3-methylimidazolium bis(trifluoromethane sulfone)amide ([C2mim][NTf2]). In a suitable polymer concentration, the SMM and MM can form ion gels in [C2mim][NTf2] under 365 nm UV light irradiation through photo-dimerization of coumarin groups in corona MM polymer chains of spherical micelles and photo-dimerization of coumarin groups in MM random polymer chains, respectively. Compared with the MM ion gel, the SMM ion gel has high mechanical properties, shear resistance and relatively high fatigue resistance. Under 254 nm UV light irradiation, photo-induced gel to jammed micelles transition for the SMM ion gel and photo-induced gel to sol transition for the MM ion gel occur due to photo-cleavage of dimer in polymer chains. Photo-induced jammed micelles - gel transition for the SMM ion gel and photo-induced sol - gel transition for the MM ion gel are reversible by alternating 365 nm and 254 nm UV light irradiation, whereby photo-healable materials can be fabricated. Compared to the MM ion gel, the SMM ion gel has high photo-healing efficiency. The electrochemical property of the SMM ion gel can be recovered completely after photo-healing.
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| 5. |
- Wu, Mingxing, et al.
(författare)
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Economical and effective sulfide catalysts for dye-sensitized solar cells as counter electrodes
- 2011
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 13:43, s. 19298-19301
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Tidskriftsartikel (refereegranskat)abstract
- Molybdenum sulfide (MoS(2)) and tungsten sulfide (WS(2)) are proposed as counter electrode (CE) catalysts in a I(3)(-)/I(-) and T(2)/T(-) based dye-sensitized solar cells (DSCs) system. The I(3)(-)/I(-) based DSCs using MoS(2) and WS(2) CEs achieved power conversion efficiencies of 7.59% and 7.73%, respectively.
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| 6. |
- Zhang, Dachuan, et al.
(författare)
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FRCD: A comprehensive food risk component database with molecular scaffold, chemical diversity, toxicity, and biodegradability analysis
- 2020
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Ingår i: Food Chemistry. - : Elsevier BV. - 0308-8146 .- 1873-7072. ; 318
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Tidskriftsartikel (refereegranskat)abstract
- The presence of natural toxins, pesticide residues, and illegal additives in food products has been associated with a range of potential health hazards. However, no systematic database exists that comprehensively includes and integrates all research information on these compounds, and valuable information remains scattered across numerous databases and extensive literature reports. Thus, using natural language processing technology, we curated 12,018 food risk components from 152,737 literature reports, 12 authoritative databases, and numerous related regulatory documents. Data on molecular structures, physicochemical properties, chemical taxonomy, absorption, distribution, metabolism, excretion, toxicity properties, and physiological targets within the human body were integrated to afford the comprehensive food risk component database (FRCD, http://www.rxnfinder.org/frcd/). We also analyzed the molecular scaffold and chemical diversity, in addition to evaluating the toxicity and biodegradability of the food risk components. The FRCD could be considered a highly promising tool for future food safety studies.
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