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Structure and Dynamics of Vapor-deposited Aqueous Solution Glasses

气相沉积水溶液玻璃的结构与动力学

基本信息

批准号：
13640382
负责人：
YAMAMURO Osamu
金额：
$ 2.37万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

In order to clarify the origin of the low energy excitation of glasses, which is one of the important problems in the physics of disordered systems, we have measured the neutron scattering and heat capacity of glassy water and several aqueous solution glasses. Two different types of solutes were taken for this study; one is well-solved solute CD_3OH and the other is less-solved solute Xe and SF_6. CD_3OH may have the effect destroying hydrogen-bond network, and Xe and SF_6 forming hydrogen-bond network through the hydrophobic hydration forming cage-like local structure. Both glasses were prepared by the low-temperature vapor-deposition technique which was developed by us.At the beginning of the study, we have measured the neutron diffraction and small angle scattering of glassy water (solvent of the present systems) and SF_6 solution glass. Annealing the samples around 120 K, which is ca. 10 K lower than the glass transition temperature, reduced average mass density and density fluctuation around 0.1 Å^<-1>. Then we measured inelastic neutron scattering of the CD_3OH, Xe and SF_6 aqueous solution glasses with several concentrations. CD_3OH increased the intensity of the low-energy excitation while Xe and SF_6 reduced the intensity. These effects were enhanced by the increase of solute concentration. Annealing around 120 K also reduced the intensity of the low-energy excitation. By combining all of the present results, we have concluded that the origin of the low energy excitation of hydrogen-bonded network glasses is the nano-scale disorder and distortion due to partially broken hydrogen bonds.At present, the above results have been published in five international journals, We had good response in all of the eight (four overseas and four domestic) international meetings where the present results were reported.

为了阐明无序体系物理学中的重要问题之一--玻璃低能激发的起源，我们测量了玻璃态水和几种水溶液玻璃的中子散射和热容。本研究采用了两种不同类型的溶质，一种是溶解度较好的溶质CD_3OH，另一种是溶解度较低的溶质SO_4和SF_6。CD_3OH可能具有破坏氢键网络的作用，而SiO_2和SF_6通过疏水水化作用形成氢键网络，形成笼状局部结构。这两种玻璃都是用我们自行研制的低温气相沉积技术制备的，在研究之初，我们测量了玻璃态水（本系统的溶剂）和SF_6溶液玻璃的中子衍射和小角散射。在120 K左右退火样品，这是约。比玻璃化转变温度低10 K，降低了平均质量密度和密度波动约0.1 μ m<-1>。在此基础上，我们测量了不同浓度的CD_3OH、Na_2SO_4和SF_6水溶液玻璃的中子非弹性散射。CD_3OH使低能激发强度增加，而SO_4和SF_6使低能激发强度减弱。溶质浓度的增加增强了这种效应。120 K左右的退火也降低了低能激发的强度。综合以上研究结果，我们认为氢键网络玻璃低能激发的根源是氢键部分断裂引起的纳米尺度无序和畸变，目前，上述研究结果已在五种国际期刊上发表，在报道本研究结果的八次国际会议（国外四次，国内四次）上均获得了良好的反响。