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明胶水溶液分形性质的光散射研究 被引量:3
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作者 张渭滨 《光学技术》 EI CAS CSCD 1998年第2期82-86,90,共6页
本文通过动态光散射技术并结合静态光散射及粘滞系数实验研究了明胶水溶液在不同温度、不同浓度下的分形性质。当T>Tgel时(Tgel为胶凝临界温度),水为明胶的良好溶剂。明胶分子在水溶液中符合自避无规行走模型,分维df=... 本文通过动态光散射技术并结合静态光散射及粘滞系数实验研究了明胶水溶液在不同温度、不同浓度下的分形性质。当T>Tgel时(Tgel为胶凝临界温度),水为明胶的良好溶剂。明胶分子在水溶液中符合自避无规行走模型,分维df=5/3。当T<Tgel时,明胶水溶液需经历从溶液到凝胶的胶凝过程。在胶凝过程中,动态光散射弛豫谱分段具有指数衰减和随后的伸展指数两种模式,且伸展指数衰减的宽度参数β逐渐从0.8减少到胶凝点的0.67,与此相对应,分维由5/3逐渐增加到2.0。在胶凝点,通过静态光散射及粘滞系数实验测得分维为2.0。 展开更多
关键词 明胶水溶液 分形 光散射 动态 静态 粘滞系数
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高于胶凝临界温度的明胶水溶液弛豫谱研究 被引量:1
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作者 张渭滨 《华侨大学学报(自然科学版)》 CAS 1998年第3期239-244,共6页
在高于胶凝临界温度条件下,半稀明胶水溶液的动态光散射弛豫谱存在三段弛豫过程,即弛豫时间小于50μs的指数衰减过程、幂律衰减过程和伸展指数衰减过程.后两个过程可归因于分形构象的反常扩散,其方均位移分别为〈R2〉∽lnt... 在高于胶凝临界温度条件下,半稀明胶水溶液的动态光散射弛豫谱存在三段弛豫过程,即弛豫时间小于50μs的指数衰减过程、幂律衰减过程和伸展指数衰减过程.后两个过程可归因于分形构象的反常扩散,其方均位移分别为〈R2〉∽lnt和〈R2〉∽tβ(β<1),宽度参数与明胶分子分数维和分形子谱维数有关. 展开更多
关键词 明胶 光散射 水溶液 胶凝临界温度 驰豫谱
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Molecular diffusion in ternary poly(vinyl alcohol)solutions
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作者 Katarzyna Majerczak Ophelie Squillace +2 位作者 Zhiwei Shi Zhanping Zhang Zhenyu J.Zhang 《Frontiers of Chemical Science and Engineering》 SCIE EI CSCD 2022年第6期1003-1016,共14页
The diffusion kinetics of a molecular probe-rhodamine B-in ternary aqueous solutions containing poly(vinyl alcohol),glycerol,and surfactants was investigated using fluorescence correlation spectroscopy and dynamic lig... The diffusion kinetics of a molecular probe-rhodamine B-in ternary aqueous solutions containing poly(vinyl alcohol),glycerol,and surfactants was investigated using fluorescence correlation spectroscopy and dynamic light scattering.We show that the diffusion characteristics of rhodamine B in such complex systems is determined by a synergistic effect of molecular crowding and intermolecular interactions between chemical species.The presence of glycerol has no noticeable impact on rhodamine B diffusion at low concentration,but significantly slows down the diffiision of rhodamine B above 3.9%(w/v)due to a dominating steric inhibition effect.Furthermore,introducing surfactants(cationic/nonionic/anionic)to the system results in a decreased diffusion coefficient of the molecular probe.In solutions containing nonionic surfactant,this can be explained by an increased crowding effect.For ternary poly(vinyl alcohol)solutions containing cationic or anionic surfactant,surfactant-polymer and surfactant-rhodamine B interactions alongside the crowding effect of the molecules slow down the overall diffiisivity of rhodamine B.The results advance our insight of molecular migration in a broad range of industrial complex formulations that incorporate multiple compounds,and highlight the importance of selecting the appropriate additives and surfactants in formulated products. 展开更多
关键词 fluorescence correlation spectroscopy poly(vinyl alcohol) anomalous diffusion crowding effects dynamic light scattering binding effects rhodamine B
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