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高分子凝胶的体积相变 总被引:4,自引:0,他引:4
本文概要地介绍了高分子凝胶体积相变的基础理论,较系统地综述了近10年来利用温度、pH值、光、电、生化反应等控制体积相变研究的进展,对有关的应用也作了简单的介绍. 相似文献
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The photophysical and electrochemical properties of a family of oligothiophene derivatives in solution werestudied.It was found that the cyano and the vinyl group could increase fluorescence yield in solution,while theformyl and carboxyl group could decrease energy gap.With increasing the chain length of thiophene ring,the oxi-dation potential could be decreased. 相似文献
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Pickering乳液模板法制备Janus粒子 总被引:4,自引:0,他引:4
本文以SiO2粒子稳定的水包油(O/W)型Pickering乳液作为模板, 在乳液连续相进行SI-ATRP, 将聚合物刷接枝到SiO2粒子外半表面, 破乳得到半修饰的Janus粒子. 相似文献
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高分子物理是化学或高分子材料等专业本科生的必修课,亚浓溶液是联系获诺贝尔奖的高分子溶液两大理论体系———平均场理论和标度理论的重要概念,对理解高分子物理的基本理论体系非常重要。本文从介绍亚浓溶液的概念入手,阐述了标度理论中高分子溶液渗透压公式的来源,指出了两个理论体系不同的思想基础和不同的物理方法,给出了改善教学方法的建议。通过这个例子,强调了不仅需要传授知识,了解知识产生和发展的过程对培养学生的创新能力更为重要。 相似文献
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荧光光谱跟踪结冷胶水溶液的溶液-凝胶转变 总被引:2,自引:0,他引:2
将异硫氰酸荧光黄(FITC)标记在结冷胶分子链,用荧光光谱跟踪了结冷胶水溶液凝胶化过程中FITC荧光强度和各向异性比的变化.结果表明在结冷胶的凝胶化转变中,FITC的荧光相对强度和各向异性随温度降低而增大,在某一温度荧光相对强度和各向异性比对温度的曲线出现了明显的转折点,这个转折点的温度低于流变温度扫描曲线中G′=G″的温度.利用荧光的方法确定物理交联体系的关于重均聚合度和凝胶分数的相关临界指数γ和β.γ和β不符合Flory-Stockmayer和逾渗模型的预测. 相似文献
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BINDING OF IONIC SURFACTANTS ON OPPOSITELY CHARGED POLYELECTROLYTES OBSERVED BY FLUORESCENCE METHODS
Our recent studies concerning the binding of ionic surfactants on oppositely charged polyelectrolytes observedwith fluorescence techniques are reviewed. The cationic surfactants cetyltrimethylammonium bromide (CTAB),dodecyltrimethylammonium chloride (DTAC), and nonionic surfactant octaethylene glycol monododecyl ether (C_(12)E_8) wereallowed to bind on anionic poly(2-acrylamido-2-methylpropanesulfonic acid) (PAMPS) and its pyrene and/or naphthalenelabeled copolymers. The relative excimer emission intensity I_E/I_M of a cationic probe l-pyrenemethylamine hydrochloride(PyMeA·HCl) and the non-radiative energy transfer (NRET) I_(Py)/I_(Np) of naphthalene to pyrene for labeled polyelectrolyteswere chosen to monitor the binding process and the conformation change of surfactant-bound polyelectrolytes. The 1:1aggregation of polyelectrolyte-CTAB with respect to the charge was found as long as the CTAB concentration was slightlyhigher than its critical aggregation concentration (CAC). The intermolecular NRET indicated that the CTAB-boundpolyelectrolytes aggregated together through the hydrophobic interaction between the CTAB tails. However, neither 1:1polyelectrolyte-DTAC aggregation nor intermolecular aggregation of DTAC-bound polyelectrolyte was observed owing to itsweaker hydrophobicity of 12 carbon atoms in the tail, which is shorter than that of CTAB. As known from the fluorescenceresults, nonionic surfactant C_(12)E_8 did not bind on the anionic polyelectrolytes, but the presence of PAMPS promoted themicelle formation for C_(12)E_8 at the CAC slightly below its critical micelle concentration (CMC). The solid complex of dansyllabeled AMPS copolymer-surfactant exhibited a decrease in local polarity with increasing charge density of thepolyelectrolyte or with alkane tail length of the surfactant. SAXS suggested a lamella structure for the AMPS copolymer-surfactant solid complexes with a long period of 3.87 nm for CTAB and 3.04 nm for DTAC, respectively. 相似文献
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水溶性高分子聚集行为荧光非辐射能量转移研究进展 总被引:4,自引:0,他引:4
评述了近几年荧光非辐射能量转移有疏水改性聚电解质的疏水聚集、高分子水溶液相变伴随的分子链塌陷、水溶性高分子与表面活性剂的相互作用等研究中的新进展,阐明了非辐射能量转移技术在水溶性高分子研究中的重要作用。 相似文献
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利用荧光非辐射能量转移观察磺酸基聚电解质分子链形态 总被引:2,自引:0,他引:2
2-丙烯酰胺基-2-甲基丙磺酸(AMPS)与N,N-二甲基丙烯酰胺(DMAA)共聚合成了一系列电荷密度为5%~99%的强聚电解质,并分别用萘和芘标记.随试样电荷密度升高,用分子间非辐射能量转移(NRET)测定的聚电解质接触质量浓度ρ*从0.55减小到0.25g/L,比激基缔合物荧光测定的ρ*约小一个数量级.在稀溶液范畴内,随试样电荷密度增加,分子链间的NRET先减弱,至AMPS质量分数达30%后又增强.该现象可用Manning的反离子凝聚与聚电解质聚集理论予以定性说明. 相似文献