| 1. |
- Alexakis, Alexandros Efraim, et al.
(författare)
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Modification of CNF‐Networks by the Addition of Small Amounts of Well‐Defined Rigid Cationic Nanolatexes
- 2022
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Ingår i: Macromolecular Chemistry and Physics. - : Wiley. - 1022-1352 .- 1521-3935. ; 224:1, s. 2200249-2200249
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Tidskriftsartikel (refereegranskat)abstract
- Cellulose nanofibril (CNF)-networks are modified by the addition of small amounts (below 10 wt%) of well-defined cationic nanolatexes synthesized through reversible addition–fragmentation chain-transfer-mediated polymerization-induced self-assembly (PISA). Minute amounts of nanolatex inclusions lead to increased tensile and shear moduli, indicating that nanolatexes can act as bridging-points between CNFs. At higher nanolatex content, this stiffening effect is lost, likely due to interactions between nanolatexes leading to plasticization. The influence of nanolatex content and size on interparticle distance is discussed and is used as a tool to understand the effects observed in macroscopic properties. Upon annealing, the stiffening effect is lost due to the softening of the nanolatexes, indicating that the core–shell morphology is a prerequisite for this effect. These systems form a versatile platform to develop fundamental insights into complex condensed colloidal systems, to ultimately aid in the development of new sustainable material concepts.
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| 2. |
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| 3. |
- Fuoco, Tiziana, PhD, 1986-, et al.
(författare)
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Multipurpose Degradable Physical Adhesive Based on Poly(d,l-lactide-co-trimethylene Carbonate)
- 2020
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Ingår i: Macromolecular Chemistry and Physics. - : Wiley. - 1022-1352 .- 1521-3935. ; 221:10
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Tidskriftsartikel (refereegranskat)abstract
- Solutions of amorphous poly(d,l-lactide-co-trimethylene carbonate)s (PDLTMCs) in ethyl acetate work as solvent-based physical adhesives through diffusion mechanisms for a variety of aliphatic polyester-based adherents. The random PDLTMCs with a trimethylene carbonate content of 11, 16, and 20 mol% are synthesized in bulk, achieving high molecular weight, M-n, up to 128 kg mol(-1) and dispersity around 1.7. The PDLTMCs are amorphous and have a glass transition temperature in the range 34.7 to 43.6 degrees C and in agreement with the theoretical values calculated using the Fox equation. The mechanical and surface properties of the PDLTMCs are tested preparing solvent cast films, which are soft and tough and, although they have a higher contact angle than the parent homopolymer, they show higher water uptake capacity. The potential application as adhesives of the synthesized PDLTMCs is evaluated by preparing a 20 wt% solution in ethyl acetate and testing them by adhering films with different compositions as well as constructs having different geometries and surface roughness. The results demonstrate that the adhesion strength is higher on adherent films having similar chemical compositions as the adhesives and on surfaces having similar compositions to each other but different roughness. The similar chemical nature of the adhesive and adherent probably favors the diffusion mechanism through which adhesion takes place.
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| 4. |
- Guo, Pengzhi, et al.
(författare)
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Twisted Alkylthiothien-2-yl Flanks and Extended Conjugation Length Synergistically Enhanced Photovoltaic Performance by Boosting Dielectric Constant and Carriers Kinetic Characteristics
- 2021
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Ingår i: Macromolecular Chemistry and Physics. - : Wiley. - 1022-1352 .- 1521-3935. ; 222:12
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Tidskriftsartikel (refereegranskat)abstract
- Alternating conjugated polymers (CPs), derived from 2-ethylhexylthiothiophen-2-yl (TS) or 2-ethylhexylthiophen-2-yl (T) flanked dithieno[3,2-d:3,2-d ']benzo[1,2-b:4,5-b ']dithiophene (DTBDT) and diketopyrrolo-pyrrole (DPP) termed as PDTBDT-TS-DPP and PDTBDT-T-DPP, are prepared and characterized. It is found that the PDTBDT-TS-DPP not only exhibits slightly deepening the highest occupied molecular orbital energy levels, and similar absorption, etc., but also presents higher dielectric constant (epsilon(r)) of 6.7 at 1 kHz in contrast to 3.2 for PDTBDT-T-DPP, which are even higher than those of 4.3 and 3.0 for PBDT-TS-DPP/PBDT-T-DPP generated from TS and T flanked benzo[1,2-b:4,5-bMODIFIER LETTER PRIME]dithiophene and DPP. Beyond that, the power conversion efficiency of 8.17% for the inverted photovoltaic devices from DPP-based CPs, is achieved from PDTBDT-TS-DPP. The alkylthio side chains are used in the DTBDT of the larger twisting angles of TS flanks and longer conjugation length, synergistically contribute to the highest dipole moments, and then lead to the enhancement of epsilon(r), thus devoted the modification exciton dissociation and charge carriers kinetic characteristics. To the authors' knowledge, it is the first time to report that epsilon(r) of the CPs is connected with the twisting angle of flanks and conjugation length of the building blocks, besides the use of functional side chains and atoms.
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| 5. |
- Kee, Seyoung, et al.
(författare)
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Tuning the Mechanical and Electrical Properties of Stretchable PEDOT:PSS/Ionic Liquid Conductors
- 2020
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Ingår i: Macromolecular Chemistry and Physics. - : John Wiley & Sons. - 1022-1352 .- 1521-3935. ; 221:23
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Tidskriftsartikel (refereegranskat)abstract
- Conducting polymers (CPs) constitute a promising building block to establish next-generation stretchable electronics. However, achieving CPs with both high electrical conductivity and outstanding mechanical stretchability beyond flexibility is still a major challenge. Therefore, understanding the key factors controlling such characteristics of CPs is required. Herein, a method to simultaneously manipulate the mechanical and electrical properties of a representative CP, PEDOT:PSS, by modifying ionic liquid (IL) additives is reported. The cation/anion modification of ILs distinctly improves the electrical conductivity of PEDOT:PSS up to ≈1075 S cm−1, and the PEDOT:PSS/IL films showing higher conductivity also exhibit superior electromechanical stretchability, enabling them to maintain their initial conductivity under a tensile strain of 80%. Based on grazing incidence wide angle X-ray scattering and Fourier transform infrared spectroscopy analyses, it is found that the cation/anion-modified ILs control the crystallinity and π–π stacking density of conjugated PEDOT chains and the growth of amorphous PSS domains via IL-induced phase separation between PEDOT and PSS, which can be the origin of the significant conductivity and stretchability improvements in PEDOT:PSS/IL composites. This study provides guidance to develop highly stretchable CP-based conductors/electrodes.
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| 6. |
- Loaiza Rodriguez, Laura, 1990, et al.
(författare)
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Li-Salt Doped Single-Ion Conducting Polymer Electrolytes for Lithium Battery Application
- 2022
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Ingår i: Macromolecular Chemistry and Physics. - : Wiley. - 1022-1352 .- 1521-3935. ; 223
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Tidskriftsartikel (refereegranskat)abstract
- Traditionally solid polymer electrolytes (SPEs) for lithium battery application are made by dissolving a Li-salt in a polymer matrix, which renders both the Li+ cations, the charge carriers of interest, and the anions, only by-standers, mobile. In contrast, single-ion conductors (SICs), with solely the Li+ cation mobile, can be created by grafting the anions onto the polymer backbone. SICs provide the safety, mechanical stability, and flexibility of SPEs, but often suffer in ionic conductivity. Herein an intrinsically synergetic design is suggested and explored; one dopes a promising SIC, LiPSTFSI (poly[(4-styrenesulfonyl) (trifluoromethanesulfonyl)imide]), with a common battery Li-salt, LiTFSI. This way one both increases the Li+ concentration and transport. Indeed, systematically exploring doping, it is found that 50-70 wt% of LiTFSI renders materials with considerable improvements in both the (Li+) dynamics and the ionic conductivity. A deeper analysis allows to address connections between the ion transport mechanism(s) (Arrhenius/VTF), the charge carrier speciation and concentration, and the free volume and glass transition temperature. While no silver bullet is even remotely found, the general findings open paths to be further explored for SPEs in general and Li-salt doped SICs in particular.
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| 7. |
- Tang, Qingquan, et al.
(författare)
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Topological Effects on Cyclic Co-Poly(ionic liquid)s Self-Assembly
- 2023
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Ingår i: Macromolecular Chemistry and Physics. - : Wiley. - 1022-1352 .- 1521-3935. ; 224:3
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Tidskriftsartikel (refereegranskat)abstract
- Topological geometry of poly(ionic liquid)s (PILs), such as brush-like, knot-like, hyperbranched and randomly coiled, often exerts a strong influence on their self-assembly behaviors. As a primary topological form, the cyclic topology-derived effects have not been investigated on PILs, which concerns synergy of charges and zero chain end. Herein, linear and cyclic poly(ionic liquid) copolymers (co-PILs) with randomly distributed counter anions of B(Ph)4− and Br− by a template method in combination with a follow-up partial anion exchange is prepared. The self-assembly phenomena of linear and cyclic co-PILs are studied in selective solvents, where the hydrophobic counter anions B(Ph)4− and hydrophilic counter anions Br− aggregated to form cores and corona in the assembled nanospheres, showing the average size of cyclic co-PILs nanospheres is 46.2% smaller (≈120 nm) than linear co-PILs nano-assemblies (≈176 nm). Based on the CGMD simulations, the authors speculate that the spherical aggregates are formed by transitioning from micelles with gradient block-like structures, which formed by enriched hydrophobic counter anions in the core and enriched hydrophilic counter anions in the corona. These results indicate a novel synergy of topology effects and dynamic anion movements, as revealed by cyclic co-PIL self-assembly in this work.
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