准弹性中子散射研究热凝在糖水溶液中的热凝
Noriko Onoda-Yamamuro1, Yasuhiro Inamura2, Osamu Yamamuro2
1Department of Natural Sciences, School of Science and Engineering, Tokyo Denki University, Hiki-gun, Saitama 350-0394, Japan.
Gels (Basel, Switzerland)
|November 24, 2023
概括
准弹性中子散射揭示了在糖溶液中的热凝抑制了聚合物运动并加速了水的扩散. 这个过程表现出显著的hysteresis,在加热和冷却周期期间不同影响分子动力学.
科学领域:
- 材料科学 材料科学 材料科学
- 生物物理学的生物物理.
- 物理化学 物理化学
背景情况:
- 糖水溶液经历热凝,这种过渡会影响其物理性质.
- 了解分子动力学对于描述生物聚合物溶液中的sol-gel过渡至关重要.
研究的目的:
- 为了研究热凝过程中水和糖分子的动态.
- 量化凝对分子运动和扩散的影响.
主要方法:
- 使用准弹性中子散射 (QENS) 来探测分子动力学.
- 分析动态结构因子S(Q,E) 来区分水和糖运动.
- 将动态结构因子与洛伦茨函数和三角函数的和相匹配.
主要成果:
- 水分子扩散 (D) 和糖分子平均平方位移 () 随着冷却阶段的温度而下降.
- D和都显示了热凝温度 (~314 K) 周围的不连续变化.
- 在加热阶段观察到显著的歇斯底里,D和在343K以下基本保持不变.
结论:
- 热凝抑制了阿加聚合物的运动,并加速了水分子的扩散.
- 凝状态下水扩散的激活能量低于sol状态和散装水中的激活能量.
- 观察到的歇斯底里表明冷却和加热过程之间的分子动力学存在显著差异.
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