高分子溶液拥挤转变行为的研究

项目名称： 高分子溶液拥挤转变行为的研究

项目编号： No.21304003

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 滕超

作者单位： 北京大学

项目金额： 25万元

中文摘要： 对非晶物质拥挤转变的研究为凝聚态物理中悬而未决已久的基本问题-非晶"液固"转变提出了全新的理解。对于拥挤转变的研究目前主要以颗粒物质、胶体体系等类原子系统为主，鲜有对真实高分子链复杂体系拥挤转变的研究。而高分子溶液为研究软物质的拥挤转变提供了理想的对象。本项目拟以高分子溶液为研究体系，通过流变学实验方法对真实高分子体系的拥挤状态和拥挤转变进行系统研究，分别考察高分子链堆积密度、剪切应力和温度等影响拥挤体系的共性参数对于体系状态和拥挤转变附近体系动力学行为的影响；同时将研究高分子体系特有的中链缠结状态、线团尺寸、分子量等属性对于拥挤转变行为的影响，以得到高分子溶液拥挤转变的一般规律，构建高分子溶液体系普适的拥挤相图，比较高分子与类原子体系拥挤转变的异同。通过流变学动态及稳态剪切实验考察高分子溶液体系在拥挤转变区域附近的普适标度规律，进一步揭示其拥挤转变的本质。

中文关键词： 拥挤转变；玻璃化转变；流变；应力松弛；高分子受限态

英文摘要： Rearch on jamming transition of disordered systems provides us a new insight to solve the fundamental, long-pending question in condensed matter physics - the glass transition. So far, studies on jamming transition mainly focus on the atom-like systems, such as granular media, colloidal suspensions, but few of them are based on real polymer system. While polymer solution provides us an ideal system to study the jamming transition of soft matter. In this proposal, by taking polymer solution as the research object, we plan to systematically study the jammed state and jamming transition of real polymer systems based on rheology methods. The intrinsic parameters of jamming transition, such as packing density, applied shear stress and temperature, will be systematically studied. Meanwhile, the typical properties of polymers, such as the entanglement density, coil size and molecular weight, will also influence the state and dynamics during jamming transition. By taking all these factors into consideration, we expect to construct a general phase diagram of polymer solution systems. Also, the differences between polymer solution and atom-like systems during jamming transition will be illustrated. By dynamic and steady shearing experiments, we hope to study the universal scaling behavior during jamming transition of poly

英文关键词： jamming transition；glass transition；rheology；stress relaxation；confined polymer