项目名称: 嵌段共聚物层状相中片晶熔融态对其玻璃化转变的影响
项目编号: No.21274059
项目类型: 面上项目
立项/批准年度: 2013
项目学科: 数理科学和化学
项目作者: 周东山
作者单位: 南京大学
项目金额: 80万元
中文摘要: 由低Tm和高Tg(如PDMS-PS, PEO-PS, PEO-PVCh等)两嵌段共聚物微相分离形成的层状相,为薄膜受限体系中片晶微结构和生长动力学的研究提供了很多非常理想的体系。我们认为这一体系同样适合研究受限于玻璃态片层之间可结晶嵌段的玻璃化转变行为,只要我们能够避免结晶嵌段的结晶。考虑到刚刚熔融的高分子链的取向和缠结恢复均是时间依赖的过程,我们可以通过高速降温的方法,冻结在不同结晶温度(Tc)所获得的不同片晶取向、并具有不同熔融历史的熔体,考察它们玻璃化转变行为的变化(或者是否存在变化)。相比旋转涂膜获得的支持或者自支撑超薄膜,以及由两个嵌段均为非结晶性高分子自组装形成的多层膜(如PS-PMMA),我们有望对同一样品进行链段残余应力、构象转变和缠结程度等结构因素的调节。我们希望这一项目的开展,能为受限态高分子链的玻璃化转变和松弛行为开拓新的研究体系。
中文关键词: 受限;玻璃化转变;嵌段共聚物;结晶;超快量热学
英文摘要: The ultrathin lamellar phase self-assemblied from the microphase seperation of diblock copolymer consisting of low melting temperture Tm and high glass transition temperture Tg blocks (like, PDMS-PS, PEO-PS and PEO-PVCh), has provided us with ideal system for the study of structure transition and growth kinetics of polymer lamellar crystal in the confined geommetry. Also, this system is highly justified for the study of glass transition of polymer confined in the ultrathin layer, given fast cooling can avoid the crystallization of the crystalline block. Because recovery of the local orientation and entanglement of the freshly melted chains from the lamellar crystal is a time-dependent process, we can freeze the melt with different chain orientation and melting history, and investigate how these factors influence the confinning effect. Compared with the ultrathin supported or self-surpporting film prepared by spin-coating, and multilayer consisting of both non-crystalline blocks, this system has the advantage to controll the residual stress, conformation change or entanglement degree. We hope this work can reveal new system for the study of glass transition and relaxation behaviors of polymers confined in the ultrathin films.
英文关键词: confinement;glass transition;block copolymer;crystallization;ultrafast calorimetry