化学法制备高分子水凝胶的研究进展

综述了近年来采用化学法制备高分子水凝胶的研究工作进展。     

智能水凝胶在生物医学领域中的研究进展

水凝胶是最常用的生物材料之一。它们在化学和结构上的多样性使其能够在广泛的场景中使用,目前 水凝胶材料在生物医药领域主要用于药物输送、癌症治疗和伤口愈合等。聚合物网络是水凝胶的核心组成部分,赋予水凝胶最独特的功能和性质。在分子层面上可以控制水凝胶的连接方式和聚合物的网络结构。因此,在材料研发的初期,了解聚合物网络的连接方式、结构、功能和特性,选择合适的聚合物对于制备特定功能的水凝胶至关重要。本文首先概述了水凝胶的凝胶机理和影响凝胶的因素,在分子层面上可以控制聚合物网络的形成,从而制备临床上需要的水凝胶。最后介绍了水凝胶在临床医学上的应用,展望了水凝胶材料的未来发展趋势。     

医用高分子水凝胶的设计与合成

作为一类重要的医用功能材料,高分子水凝胶可望在药物控释、软骨支架构建、活性细胞封装等方面获得广泛应用。综述了基于化学交联和物理交联的有关水凝胶的设计与合成方法,重点介绍了通过自由基共聚反应、结构互补基团间化学反应形成的化学交联水凝胶以及通过荷电相反离子问相互作用、两亲性嵌段或接枝共聚物疏水缔合、结晶与氢键相互作用形成的物理交联水凝胶。     

响应性水凝胶及其在生物医药领域应用研究进展

响应性水凝胶又称"智能水凝胶",是以水凝胶为基础,经修饰响应多种理化性质及微小环境变化,从而改变自身性质的一类水凝胶。响应性水凝胶目前广泛应用于生物医药领域、材料领域等,如:制备pH响应性水凝胶负载阿霉素(DOX)治疗癌症,温度响应性水凝胶制作3D生物打印材料用于创伤修复,葡萄糖响应性水凝胶治疗糖尿病足等。本文介绍了响应性水凝胶研究的国内外发展动态,包括响应性水凝胶的制备、修饰方法及其在生物医药领域的应用,并对未来的发展方向进行了讨论与展望。     

高分子增强水凝胶的制备策略及机理

高分子水凝胶是一类在医学、制药、软骨组织工程、人工肌肉、仿生制动器和吸附剂等领域具有广泛应用前景的高分子材料,但是由于高分子水凝胶的机械强度较低,很大程度上限制了其应用。近年来,高分子增强水凝胶受到许多国内外科学家的广泛关注。研究证明,增强后的高分子水凝胶具有抗溶胀性、较强的韧性、超高机械强度的特点,具有显著的应用价值。本文介绍了高分子水凝胶的概念、高分子水凝胶增强的机理,并详细归纳了高分子增强水凝胶的制备策略,主要包括浸泡在电解质溶液中制备水凝胶、纳米复合水凝胶、多网络水凝胶,总结了最新的研究进展。最后,基于目前高分子水凝胶存在的一些问题(如部分水凝胶生物相容性差、水凝胶在人体内无法降解、导电性差等),对未来高分子增强水凝胶发展以及可用于扩大天然材料应用领域、生物领域、环境修复领域做出了展望。     

天然高分子材料水凝胶的制备及其应用进展

水凝胶是一种由高分子聚合物构成的三维网络材料,用自然界中天然存在的高聚物及其衍生物材料构建水凝胶,具有生物相容性、环境敏感性高、生物可降解性和对环境无污染等优势。本文介绍了近几年天然高分子水凝胶材料在医药卫生、食品、农业和环保等领域的应用情况;并按材料来源的不同,分类综述了蛋白质、多肽类水凝胶,海藻多糖水凝胶,动物多糖水凝胶,植物多糖水凝胶,其改性和制备复合水凝胶的最新技术、功能特性以及应用领域;最后对天然高分子水凝胶制备的改进方向和重点应用领域进行了展望。     

小分子与高分子混合凝胶研究进展

凝胶作为一种半固态的软物质材料近年来得到很多关注。高分子和小分子都可以作为凝胶的胶凝剂,但是由于在形成过程中两者形成的结构交联与否对形成的凝胶影响很大,表现出了明显的不同。而小分子高分子混合凝胶能整合两者的优势,使混合凝胶兼具小分子凝胶的刺激响应性和高分子凝胶的力学性能。本文从高分子凝胶与小分子凝胶的差异化和互补性方面入手,总结了小分子和高分子的混合凝胶的研究进展。     

纳米水凝胶合成方法的研究进展

粒径在1～1000nm范围内的纳米水凝胶可用于药物输送、医学诊断、生物传感器和生物物质分离等领域,近年来受到国内外普遍关注。本文从合成纳米水凝胶的原料入手,分别从单体与交联剂聚合和聚合物后交联两个方面综述了纳米水凝胶合成方法的研究进展。通过单体与交联剂聚合合成纳米水凝胶的方法主要有三种:沉淀聚合法、反相乳液聚合法和微模板聚合法。采用聚合物后交联合成纳米水凝胶的方法主要有四种:沉淀/交联法、乳化/交联法、自组装/交联法和微模板成型/交联法。另外,对这些合成方法的优缺点进行了评述,并对生物医用纳米水凝胶合成方法的研究方向提出了一些粗浅的看法。     

智能高分子及水凝胶的响应性及其应用

结合一些范例综述了智能水凝胶的基本概念、种类以及智能高分子响应环境温度、pH值和光信号刺激的相转变行为, 简要介绍了该类高分子在农林业、卫生等领域中的应用, 并对其发展前景作了展望.     

基于多肽和蛋白质的水凝胶研究进展

基于多肽和蛋白质的水凝胶体系作为生物材料的一个重要种类,受到了广泛关注,近年来更得到了长足的进步。其凝胶化的机制既可以是侧基之间的物理组装和聚集,也可以是反应性残基之间的可控化学反应。两者协同作用可进一步促进其功能改性。多肽和蛋白质独有的生物活性及其结构和功能上的多样性和可调性为生物材料的发展提供了诸多可能,展现出广泛的应用前景。本文对基于多肽和蛋白质的水凝胶的设计、制备和应用等研究进展进行了简要的介绍与总结,并对该领域的进一步发展进行了展望。     

Recent progress in polymer hydrogel bioadhesives

Adhesive hydrogels have broad applications in tissue adhesives, hemostatic agents, and biomedical sensors. Various bio-inspired glues and synthetic adhesives are clinically used as conventional hemostatic agents and auxiliary tools for wound closure. Medical adhesives are needed to effectively and quickly control bleeding, thereby reducing the risk of complications caused by severe blood loss. Medical sensors need to have excellent skin compliance, mechanical properties, sensitivity, and biological safety. This review focuses on recent progress in adhesive hydrogel systems, their structures, adhesion mechanisms, construction strategies, and emerging applications in the biomedical field.     

Radiation preparation and thermo-response swelling of interpenetrating polymer network hydrogel composed of PNIPAAm and PMMA

Interpenetrating polymer network (IPN) hydrogel composed of hydrophilic poly(N-isopropylacrylamide) (PNIPAAm) and hydrophobic poly(methyl methacrylate) (PMMA) were synthesized by sequential IPN method using γ-rays from ⁶⁰Co source. Compared with pure PNIPAAm hydrogel, PNIPAAm/ PMMA IPN hydrogel not only behaved with obvious temperature sensitivity, but also had higher mechanical strength. The shrinking rate of the prepared IPN hydogel was slower than that of PNIPAAm hydrogel and the relative shrinkage was higher than that of PNIPAAm hydrogel. The IPN hydrogel with less PMMA was not stable while with more PMMA it was quite stable. In addition, the release of Methylene Blue (MB) from the IPN hydrogel was slower than that from PNIPAAm hydrogel as well.     

Self-discharge characteristics of an electric double-layer capacitor with polymer hydrogel electrolyte

An electric double-layer capacitor (EDLC) was assembled with the polymer hydrogel electrolyte prepared from cross-linked potassium poly(acrylate) (PAAK) and KOH aqueous solution, and the self-discharge characteristics were investigated. The EDLC cell with the polymer hydrogel electrolyte showed lower voltage decay on open circuit than that with a KOH aqueous solution. Moreover, it was found that the leakage current of the EDLC cell was markedly suppressed by using the polymer hydrogel electrolyte. The suppression was enhanced with increasing PAAK content in the electrolyte. These results strongly suggest that the PAAK plays an important role in the suppression of self-discharge.     

Trends in industrial polymer research

In the past decades a shift in paradigm took place in industrial polymer research for structural materials. Only a few new polymers based on new monomeric building blocks were developed. The main focus is now on tailoring improved “old polymers” with well-defined structure and properties based on a set of low cost “old” monomers using controlled polymerization mechanisms.     

功能配位聚合物研究进展

主要就配位聚合物在气体吸附、手性拆分和催化、分子磁体方面的研究进展进行了综述,指出配位聚合物作为潜在的新型功能材料近年来得到了科学家的普遍关注;列举了近年来这类配位聚合物的研究成果和开发进展,并对其发展前景作了展望.     

Electric field sensitivity of conducting hydrogels with interpenetrating polymer network structure

In this article, we reported the synthesis, structure and electric field sensitivity of polyacrylate/polyaniline (PAA/PANI) and poly(2-acrylamido-2-methyl propylsulfonic acid-acrylic acid)/polyaniline [P(AMPS-AA)/PANI] conducting hydrogels with an interpenetrating polymer network (IPN) structure. Scanning electron microscope showed that the conducting hydrogels presented porous structures consisting of PANI nanofibers. The results of Fourier-transform infrared and X-ray diffraction revealed that the PANI was in its conductive emeraldine state and partial crystallization. The unique morphology and molecular structure of the conducting hydrogels were expected to show unusual electric field responses. The conducting hydrogels were subjected to an electric field in NaCl solution for bending behaviors. It was demonstrated that the electric field response was improved by increasing aniline dosage, applied voltage and concentration of aqueous NaCl solution. The bending mechanism was attributed to polyelectrolyte hydrogel matrix and emeraldine PANI nanofibers.     

Chitosan-based self-healing hydrogel for bioapplications

A chitosan-based biocompatible self-healing hydrogel has been facilely prepared and used for bioapplications.     

Removal of methylene blue dye from aqueous solution by semi‐interpenetrating polymer network hybrid hydrogel: Optimization through Taguchi method

In this study, sodium humate/poly(acrylamide‐co‐methacrylic acid)/kaolin semi‐interpenetrating polymer network hybrid hydrogel was synthesized as an effective adsorbent for the removal of methylene blue. The morphological and structural properties, and swelling behavior in distilled water and various environments of hybrid hydrogel were investigated with different analyses and tests. The equilibrium swelling percent of hybrid hydrogel reached to 37,000% in 240 min. The parameters (agitation time, concentration, dose, temperature, and pH) affecting adsorption process for methylene blue were optimized using Taguchi method. The data obtained in optimum conditions were well fitted to Langmuir adsorption isotherm and maximum adsorption capacity was determined as 833. 33 mg/g. In the light of the results, the utilization of hybrid hydrogel with high swelling capacity is foreseen as a favored adsorbent in several separation processes. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 1070–1078     

Recent strategies to enhance the performance of polymer monoliths for analytical separations

This review summarizes recent developments made in the incorporation of functional materials into organic polymer monoliths, together with new monolithic forms and formats, which enhance their application as supports and stationary phase materials for sample preparation and chromatographic separations. While polymer monoliths are well‐known supports for the separation of large molecules, recent developments have been made to improve their features for the separation of small molecules. The selectivity and performance of organic polymer monoliths has been improved by the incorporation of different materials, such as metal‐organic frameworks, covalent organic frameworks, or other types of nanostructured materials (carbon nanohorns, nanodiamonds, polyoxometalates, layered double hydroxides, or attapulgite). The surface area of polymer monoliths has been significantly increased by polymer hypercrosslinking, resulting in increased efficiency when applied to the separation of small molecules. In addition, recent exploration of less conventional supports for casting polymer monoliths, including photonic fibres and 3D printed materials, has opened new avenues for the applications of polymer monoliths in the field of separation science. Recent developments made in these topics are covered, focusing on the strategies followed by the authors to prepare the polymer monoliths and the effect of these modifications on the developed analytical applications.     

Local order and shape of a polymer chain in an external electric field

A solution of polymer chains in the presence of an external electric field is considered. Dipole-like interactions between polymer chain segment-vectors and the electric field are assumed to be proportional to the cosine of the angle between the segment-vector and the direction of the electric field. Parameters characterizing the shape of the chain (i.e., the chain end-to-end distance and cross-section per chain), and parameters describing the local order at the segmental and chain level (i.e., moments of the first and second Legendre polynomials 〈P₁〉 and 〈P₂〉 are calculated. The optical anisotropy and the molecular shape change induced by the external electric field are discussed.