Elasticity of Soft Materials

Weitz提出的研究将开发一种新颖的、通用的、广泛适用的方法，利用光散射来非模糊地测量“软”材料的弹性特性。这项新技术将大大扩展弹性特性测量的范围，并将直接将介质的响应与其内部动力学联系起来。该技术将被用于获得对各种无序或玻璃状“软”材料弹性起源的新见解，包括靠近玻璃化过渡的胶体悬浮液、聚合物溶液和聚合物熔体、压缩乳液、生物聚合物网络（如DNA和肌动蛋白）和缓慢老化系统。拟议的研究将开发一种新颖的、基于激光的方法，以非侵入性地探测各种材料的基本特性，包括凝胶、生物分子，如DNA和肌动蛋白（一种赋予细胞强度的纤维分子）。该技术将测量材料的机械性能，从而确定它们的行为是更像“固体”（如明胶）还是更像液体（如蜂蜜），并将大大扩展传统方法的适用范围。通过这些研究获得的知识将为所调查材料的机械性能的潜在起源提供新的见解。它还将促进材料在商业或医疗领域的应用。＊＊＊

w:\awards\awards96\*.doc 9631279 Weitz The proposed research will develop a novel, general purpose and widely applicable method to use light scattering to non-evasively measure the elastic properties of 'soft' materials. This new technique will extend significantly the range over which elastic properties an be measured and will directly relate the response of the medium to its internal dynamics. The technique will be exploited to obtain new insight into the origin of the elasticity in a variety of disordered, or glassy, 'soft' materials, including colloidal suspensions near their glass transition, polymer solutions and polymer melts, compressed emulsions, networks of bio-polymers such as DNA and actin, and slowly aging systems. %%% The proposed research will develop a novel, laser-based method to non-invasively probe essential properties of a wide class of materials, including gels, and biomolecules such as DNA and actin, a fibrous molecule that imparts strength to cells. The technique will measure the mechanical properties of the materials, thus determining whether their behavior is more 'solid- like' (as in gelatin) or fluid-like (as in honey), and will significantly extend the range of applicability of traditional methods. The knowledge gained by these studies will provide new insight into underlying origins of the mechanical properties of the materials investigated.. It will also facilitate the application of the materials in commercial or medical areas. ***