Elasticity of Soft Materials

w：\awards\awards96\*.doc 9631279 Weitz 这项研究将开发一种新的，通用的和广泛适用的方法，使用光散射非回避测量“软”材料的弹性性能。 这种新技术将大大扩展弹性特性的测量范围，并将介质的响应与其内部动力学直接联系起来。该技术将被利用，以获得新的洞察力的弹性起源， 各种无序的或玻璃状的“软”材料，包括接近其玻璃化转变的胶体悬浮液，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）以及缓慢老化系统。 这项拟议的研究将开发一种新型的基于激光的方法，以非侵入性方式探测各种材料的基本特性，包括凝胶和生物分子，如DNA和肌动蛋白，一种赋予细胞强度的纤维分子。 该技术 将测量机械性能 的 材料，从而确定它们的行为是更像“固体”（如明胶）还是更像流体（如蜂蜜），并且将显著扩展传统方法的适用范围。 这些研究所获得的知识将为研究材料的机械性能的根本起源提供新的见解。 材料调查 它还将促进 该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. ***