基于荧光水凝胶的功能表面器件

基于水凝胶体系的功能材料及应用发展迅速,在包括组织工程、能源存储、柔性器件等领域展现出广阔的应用前景。采用聚乙烯醇、壳聚糖和琼脂糖构建水凝胶主体结构,并添加羟乙基纤维素增塑保湿,添加碳量子点赋予材料荧光效应。制备获得了兼具有优良的自修复性能和优异拉伸性能的多网络结构水凝胶,具有高达33 MPa的拉伸强度并能够在多种媒介环境下实现快速的自修复,在空气中60 s自修复效率达93%。研究发现复合水凝胶材料的荧光强度同表面所受压强呈负相关性,而同其拉伸伸长率呈正相关。数据拟合证实,通过检测水凝胶的荧光强度可以监控其变形率,而结合水凝胶和仿壁虎表面结构制备出能够黏附于多种表面的压强检测器,通过对器件荧光强度的检测能够探测液下环境压强。该研究拓展了荧光水凝胶材料的应用途径,有望用于液下压强探测、工程结构失效监控等。     

双重动态共价键交联纳米纤维素导电水凝胶及其柔性传感器

自愈合导电水凝胶因其良好的自愈合性能与导电性能,在柔性可穿戴设备中具有巨大的应用前景。以4-甲酰基苯硼酸（Bn）交联聚乙烯醇（PVA）和聚乙烯亚胺（PEI）构建基于硼酸酯键和亚胺键的双重动态交联水凝胶网络,引入聚吡咯修饰的纤维素纳米纤维（PPy@CNF）构建了具有良好自愈合和导电性的PBP-PPy@CNF纳米复合水凝胶。结果表明,当PPy@CNF的质量分数为0.8%时,水凝胶的力学性能最佳,其最大应力可达6.65kPa,断裂拉伸应变可达2080%,电导率为2174μS/m。基于该水凝胶的电阻式传感器具有良好的稳定性和重复性,在应变检测范围0~800%内,灵敏因子GF可分为三个线性响应区域,分别是0~200%（GF₁=2.82）、200%~600%（GF₂=7.15）和600%~800%（GF₃=12.85）,该传感器能有效检测人体不同部位的运动,可应用于可穿戴传感设备。     

离子凝胶复合吸附剂的制备及空气取水性能

制备了一种LiCl复合可得然离子凝胶,并将其首次用于空气取水性能研究。在不同吸附温度、吸附湿度的开式环境中,完成了复合吸附剂的水蒸气吸附特性研究。探究了浸渍盐的质量浓度对复合吸附剂吸附性能的影响。根据目标工况,完成了复合吸附剂组分的优化配比。对优化后的离子凝胶进行了吸附动力学和等温吸附特性研究。结果表明,15% LiCl溶液复合而成的可得然吸附剂综合性能最佳。在35℃&75%RH下,该复合吸附剂的吸附量高达3.30g/g,是传统硅胶复合吸附剂的6.6倍;在55℃&40%RH工况下实现1.66 g/g的水量脱附,是硅胶复合吸附剂的3倍。在25℃&75%RH下,可得然复合凝胶吸附剂的吸附速率K高达3.48×10^-3s^-1;该离子凝胶复合吸附剂的研究,为吸附式空气取水技术提供了基础支持。     

水凝胶的制备

主要叙述了水凝胶的各种制备方法,包括化学方法和物理方法,不同的高分子原料和不同的制备方法所得到的水凝胶的性质会有所差异,可以满足不同领域的应用需求。     

Preparation of CaCO3‐based biomineralized polyvinylpyrrolidone–carboxymethylcellulose hydrogels and their viscoelastic behavior

In the blend of natural and synthetic polymer‐based biomaterial of polyvinylpyrrolidone (PVP) and carboxymethylcellulose (CMC), fabrication of CaCO₃ was successfully accomplished using simple liquid diffusion technique. The present study emphasizes the biomimetic mineralization in PVP–CMC hydrogel, and furthermore, several properties of this regenerated and functionalized hydrogel membranes were investigated. The physical properties were studied and confirmed the presence of CaCO₃ mineral in hydrogel by Fourier transform infrared spectroscopy and Scanning electron microscopy. Moreover, the absorptivity of water and mineral by PVP–CMC hydrogel was studied to determine its absorption capacity. Further, the viscoelastic properties (storage modulus, loss modulus, and complex viscosity) of mineralized and swelled samples (time: 5–150 min) were measured against angular frequency. It is interesting to know the increase of elastic nature of mineralized hydrogel filled with CaCO₃ maintaining the correlation between elastic property and viscous one of pure hydrogel. All these properties of biomineralized hydrogel suggest its application in biomedical field, like bone treatment, bone tissue regeneration, dental plaque and tissue replacement, etc. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40237.     

快速响应型P(NIPA-co-SA)水凝胶制备及温敏性能

研究具有较高LCST且响应速率快的温敏性水凝胶。以NaCl水溶液为反应介质,采用相分离法合成了多孔水凝胶P(NIPA-co-SA)。利用傅立叶变换红外光谱仪(FT-IR)表征产物结构,并借助扫描电子显微镜、差示扫描量热法(DSC)、浊度法等手段研究了反应介质浓度对产物微观形貌、相变温度和相变响应速率的影响规律。结果表明,P(NIPA-co-SA)水凝胶具有对温度敏感的响应特性,其低临界溶解温度(LCST)可达到75℃。NaCl水溶液浓度不影响产物的LCST,且随着反应中NaCl水溶液浓度的提高,水凝胶表面逐渐出现不连续的浅而封闭的小孔到互相贯穿的开孔,水凝胶相变响应速率在一定范围内逐渐提高,具有快速响应特性。     

Accelerated Preparation of Novel Bacterial Cellulose/Acrylamide-Based Hydrogel by Microwave Irradiation

The fabrication of novel bacterial cellulose/polyacrylamide-based hydrogels by accelerated radiation by microwave was investigated. This study was designed and optimized using the Taguchi method by taking irradiation time and power as the main parameters. The results revealed the dependence of percentage gel fraction and swelling index on the synthesis parameters using a microwave. The gel fraction was proportionally increased with power and time. The bacterial cellulose fibers crosslinked with polyacrylamide polymer chain as the thermal energy in the monomer mixture quickly rose, leading to a higher degree of polymerization. A highly time-efficient processing with interchangeable parameters allows various hydrogel properties to be developed.     

Hydrogels Based on 2-Hydroxyethylmethacrylate and Chitosan: Preparation,Swelling Behavior,and Drug Delivery

The authors report preparation of chitosan by deacetylation of chitin extracted from shrimp shells. The quality of chitosan depended on the chemical extraction process, the concentration of chemicals used, soaking time, sequence of deproteination, decalcification, and deacetylation. Hydrogels composed of hydroxyethylmethacrylate and chitosan were subsequently prepared and their swelling and ibuprofen delivery kinetics at various chitosan concentrations were studied. The swelling properties of the network varied with the chitosan concentration. Furthermore, the swelling process followed second-order kinetics, while ibuprofen diffusion into the hydrogel showed Fickian behavior.     

Fluorescent Hydrogel–Textile Composite Material Synthesized by Photopolymerization

A fluorescent textile sensor and its capacities to detect pH changes in aqueous solutions have been reported. A new hydrogel-cotton fabric was obtained via surface initiated photopolymerization of 2-aminoethylmethacrylate hydrochloride, with N,N′-methylene-bis-acrylamide as a crosslinker, and fluorophore and modified eosin Y and N-methyldiethanolamine as photoinitiators. The synthesis of the modified eosin Y and a new 1,8-naphtalimide used as signal units in the hydrogel composite have been described. It has been found that the concentration of the photoinitiator affects the functional properties of the composite. pH variations influence the gel structure and this is transduced into fluorescence and color changes of the material.