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91.
Four modes of charge transfer interactions in polyaniline (PAN), viz. acid protonation, self-doping, charge transfer interactions with organic acceptors, and charge transfer interactions with surface grafted functional polymers have been studied by X-ray photoelectron spectroscopy (XPS). In the case of acid protonation, the protonation behavior of volatile and non-volatile acid differs. The structures of sulfonated leucomeraldine (LM) and nigraniline (NA) are similar to those of sulfonated and self-protonated emeraldine (EM). A substantially higher degree of charge transfer interaction with the organic acceptors is observed for EM film that has been subjected to one cycle of acid/base treatment. The charge transfer interactions with the organic acceptors have proceeded further than the pure formation of molecular complexes. Both pristine and Ar plasma or O3 pretreated EM films are susceptible to surface modifications by graft copolymerization. The protonic acid functional groups of the graft readily give rise to a self-protonated EM surface. 相似文献
92.
Yunzhe Jiang Yidong Liu Dr. Sylvain Grosjean Dr. Volodymyr Bon Dr. Patrick Hodapp Dr. Anemar Bruno Kanj Prof. Dr. Stefan Kaskel Prof. Dr. Stefan Bräse Prof. Dr. Christof Wöll Dr. Lars Heinke 《Angewandte Chemie (International ed. in English)》2023,62(20):e202218052
Molecular machines and responsive materials open a plethora of new opportunities in nanotechnology. We present an oriented crystalline array of diarylethene (DAE)-based photoactuators, arranged in a way to yield an anisotropic response. The DAE units are assembled, together with a secondary linker, into a monolithic surface-mounted metal–organic framework (SURMOF) film. By Infrared (IR) and UV/Vis spectroscopy as well as by synchrotron X-ray diffraction, we show that the light-induced extension changes of the molecular DAE linkers multiply to yield mesoscopic and anisotropic length changes. Due to the special architecture and substrate-bonding of the SURMOF, these length changes are transferred to the macroscopic scale, leading to the bending of a cantilever and performing work. This research shows the potential of assembling light-powered molecules into SURMOFs to yield photoactuators with a directed response, presenting a path to advanced actuators. 相似文献
93.
Davide Derelli Francesco Caddeo Kilian Frank Kilian Krötzsch Patrick Ewerhardt Marco Krüger Sophie Medicus Lars Klemeyer Marvin Skiba Charlotte Ruhmlieb Olof Gutowski Ann-Christin Dippel Wolfgang J. Parak Bert Nickel Dorota Koziej 《Angewandte Chemie (International ed. in English)》2023,62(43):e202307948
CuBi2O4 has recently emerged as a promising photocathode for photo-electrochemical (PEC) water splitting. However, its fast degradation under operation currently poses a limit to its application. Here, we report a novel method to study operando the semiconductor-electrolyte interface during PEC operation by surface-sensitive high-energy X-ray scattering. We find that a fast decrease in the generated photocurrents correlates directly with the formation of a metallic Bi phase. We further show that the slower formation of metallic Cu, as well as the dissolution of the electrode in contact with the electrolyte, further affect the CuBi2O4 activity and morphology. Our study provides a comprehensive picture of the degradation mechanisms affecting CuBi2O4 electrodes under operation and poses the methodological basis to investigate the photocorrosion processes affecting a wide range of PEC materials. 相似文献
94.
95.
抗菌涂料广泛应用于医疗保健、食品保鲜和医院消毒等多个行业领域。石墨烯是目前最受欢迎的纳米材料之一,在抗菌方面细菌表现出低耐药性,同时对哺乳动物细胞有较小的细胞毒性。石墨烯从物理和化学两个层面协同发挥抑菌效果,物理方面其尖锐边缘与细菌细胞膜的直接接触从而对脂质分子进行破坏性提取,而化学方面通过氧化应激所产生的活性氧以及电荷转移破坏细菌细胞膜。此外,石墨烯用于作为分散和稳定各种纳米材料的载体,且得益于材料之间的协同作用,其复合材料具有较高的抗菌效率和良好的生物相容性,目前已在抗菌包装、伤口敷料和器械表面清洁等方面投入使用。本文首先概述了石墨烯的结构、安全性以及抗菌机理,对石墨烯复合涂层所取得的重要成果进行简要总结,最后综述了石墨烯材料在支架表面改性中的研究进展,展望了石墨烯抗菌涂层的未来发展趋势。 相似文献
96.
《高分子科学杂志,A辑:纯化学与应用化学》2013,50(9):1009-1021
This article deals with the characterization of blend films obtained by mixing poly(vinyl alcohol) (PVA) and konjac glucomannan (KGM) in aqueous solution. The DTA curves of PVA/KGM blend films showed overlapping of the main thermal transitions characteristic of the individual polymers. The exothermic peak at 312°C, which resulted from the thermal degradation of the KGM, shifted slightly to a higher temperature at low PVA content (≤20 wt%). The weight-retention properties of the blend films indicated that thermal stability of the blend films were better than pure KGM film at PVA content below 20 wt%. The crystallinities, tensile strength, and elongation at break of the films increased with the PVA content, and reached the maximum values at 20 wt% PVA, then decreased. Changes in the carbonyl stretching band of KGM and hydroxyl stretching regions of KGM and PVA were detected by FTIR analysis. Those are attributable to the existence of a certain degree of inteaction between KGM and PVA, and resulted from intermolecular hydrogen bonds. Phase separation phenomena were observed by examining the surface of the blend films by SEM. 相似文献
97.
Proteins are considered potential material in natural films as alternative to traditional packaging. When gamma radiation is applied to protein film forming solution it resulted in an improvement in mechanical properties of whey protein films. The objective of this work was the characterization of mechanical and thermal properties of irradiated films based on muscle proteins from Nile Tilapia (Oreochromis niloticus). The films were prepared according to a casting technique with two levels of plasticizer: 25% and 45% glycerol and irradiated in electron accelerator type Radiation Dynamics, 0.550 MeV at dose range from 0 to 200 kGy. Thermal properties and mechanical properties were determined using a differential scanning calorimeter and a texture analyzer, respectively. Radiation from electron beam caused a slightly increase on its tensile strength characteristic at 100 kGy, while elongation value at this dose had no reduction. 相似文献
98.
采用射频等离子体增强化学气相沉积法(RF-PECVD),在玻璃和硅衬底上以230—310Pa之间的沉积气压生长微晶硅(μc-Si:H)薄膜。利用拉曼光谱和红外光谱分析样品的微结构。结果发现样品的微结构强烈依赖于沉积气压,并且存在着最佳沉积气压250Pa,在此条件下的微晶硅薄膜晶化率为60.6%,氢含量为最小值9.1%。 相似文献
99.
Nanocrystalline anatase (TiO2) films were prepared at very low temperature through a sol-gel route using titanium isopropoxide and hydrogen peroxide in
ethanol. Crystallization occurred after film deposition at 35°C in an atmosphere saturated with water vapor. Both thin and
thick films of nanocrystalline anatase were prepared. Observed particle size in crystallized films is approximately 20–40 nm
as measured with AFM. No residual organic material was apparent through FTIR after crystallization occurred. Dynamic light
scattering studies performed on this system indicate that particle size measured in solution is strongly dependent on the
amount of agitation samples received prior to measurement. 相似文献
100.
Dr. Abdul Khayum Mohammed Dr. Jésus Raya Ajmal Pandikassala Dr. Matthew A. Addicoat Safa Gaber Mohamed Aslam Dr. Liaqat Ali Dr. Sreekumar Kurungot Prof. Dinesh Shetty 《Angewandte Chemie (International ed. in English)》2023,62(29):e202304313
Hydrogen-bonded organic frameworks (HOFs) are ordered supramolecular solid structures, however, nothing much explored as centimetre-scale self-standing films. The fabrication of such crystals comprising self-supported films is challenging due to the limited flexibility and interaction of the crystals, and therefore studies on two-dimensional macrostructures of HOFs are limited to external supports. Herein, we introduce a novel chemical gradient strategy to fabricate a crystal-deposited HOF film on an in situ-formed covalent organic polymer film (Tam-Bdca-CGHOF). The fabricated film showed versatility in chemical bonding along its thickness from covalent to hydrogen-bonded network. The kinetic-controlled Tam-Bdca-CGHOF showed enhanced proton conductivity (8.3×10−5 S cm−1) compared to its rapid kinetic analogue, Tam-Bdca-COP (2.1×10−5 S cm−1), which signifies the advantage of bonding-engineering in the same system. 相似文献