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Formation Mechanism and its Control of Organic / Inorganic Network in Nanocomposite Gel

纳米复合凝胶中有机/无机网络的形成机理及其控制

基本信息

批准号：
16550181
负责人：
HARAGUCHI Kazutoshi
金额：
$ 2.3万
依托单位：
Kawamura Institute of Chemical Research
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

项目摘要

Control of the network structure of polymer gel is of particular importance not only in understanding of the origin of the advanced properties of the polymer gels, but also for designing even newer types of gels. In this project, we carried out a series of structural, mechanical and functional investigations for nanocomposite type hydrogel (NC gel) consisting of poly(N-isopropylacrylamide) (PNIPA) and inorganic clay (hectorite). (1) We firstly synthesized NC gels with various clay concentrations (C_<clay>), and studied the mechanism of forming unique organic / inorganic network structure during in-situ free-radical polymerization through changes in viscosity, optical transmittance, X-ray diffraction and mechanical properties. Then, we proposed the unique network formation mechanism, including the formation of clay-brush particles. Also, (2) we revealed that the mechanical properties (modulus and strength) of NC gels can be varied in a wide range, without sacrificing the ultra-high elon … More gation at break (1000%), depending on the C_<clay>. In particular, it was found that NC gels exhibit the extraordinarily high fracture energy (up to 3000 times that of conventional chemically-crosslinked hydrogel), and that the strength reached to 3 MPa by subsequent elongation treatment. Furthermore, we found a number of important properties of NC gels, such as (3) appearance of optical anisotropy in NC gels at above critical C_<clay>, (4) reversible force generation as a result of the coil-to-globule transition of PNIPA chains in response to cycling the temperature across the lower critical solution temperature, (5) total control of the coil-to-globule transition by incorporation of clay nano-particles, (6) the formation of unique porous morphologies with a three-layered structure in the freeze-dried state, (7) the characteristic sliding frictional behaviors with remarkable changes in the coefficient of friction at the surface of NC gels, (8) biocompatibility including implantation and antithrombogenicity, etc. Thus, many interesting and important characteristics of NC gels are clarified through this project. Less

控制聚合物凝胶的网络结构不仅在理解聚合物凝胶的高级性质的起源方面特别重要，而且对于设计甚至更新类型的凝胶也特别重要。在本项目中，我们对由聚（N-异丙基丙烯酰胺）（PNIPA）和无机粘土（锂蒙脱石）组成的纳米复合型水凝胶（NC凝胶）进行了一系列的结构、力学和功能研究。(1)首次合成了不同粘土含量（C_）的NC凝胶，通过粘度、透光率、X射线衍射和力学性能的变化，研究了NC凝胶在原位自由基聚合过程中形成独特的有机/无机网络结构的机理。<clay>提出了独特的网络形成机制，包括粘土刷状颗粒的形成。（2）NC凝胶的力学性能（模量和强度）可以在很宽的范围内变化，而不牺牲超高的拉伸强度。 ...更多信息断裂伸长率（1000%），取决于C_。<clay>特别地，发现NC凝胶表现出非常高的断裂能（高达常规化学交联水凝胶的3000倍），并且通过随后的伸长处理强度达到3MPa。此外，我们还发现了NC凝胶的一些重要性质，如（3）在高于临界C_的温度下，NC凝胶中出现光学各向异性;（4）PNIPA链响应于温度在低临界溶液温度下的循环而产生的可逆力;（5）通过掺入粘土纳米颗粒来完全控制螺旋到球的转变;（6）在冷冻干燥状态下形成独特的具有三层结构的多孔形态，<clay>（7）NC凝胶表面摩擦系数显著变化的滑动摩擦特性;（8）生物相容性，包括植入性和抗血栓性等。因此，通过本项目阐明了NC凝胶的许多有趣而重要的特性。少