【摘要】 采用耗散粒子动力学(Dissipative particle dynamics,DPD)方法研究了在剪切场作用下,环形二嵌段共聚物微观相分离过程中的形态变化.在层状(lamellae,LAM)体系中发生了微相的平行重取向和平行-垂直转变以及剪切导致的波动不稳定现象.对于穿孔层状(Perforated lamellae,PL)体系,强剪切导致了穿孔层状-柱状(Hexagonal cylinder,HEX)微相转变.在剪切场作用下,柱状体系中同样也有平行重取向发生.可以用相区破坏-相区重生的两步机理描述微相的平行重取向、平行-垂直转变以及PL-HEX转变现象.在球状相(Body centered cubic,BCC)体系中发现了剪切诱导相融合.更多还原

【Abstract】 The morphology changes of cyclic diblock polymer microphases under simple shear were studied via DPD technique. For LAM, parallel reorientation and parallel-perpendicular orientation transition phenomena were reproduced. Moreover, the undulation instability was observed. For PL, PL-HEX transition occurs under a strong shear. For HEX, parallel reorientation was identified. A two stage reorientation mechanism involving break-up and phase reformation was proposed to describe the reorientation process for both LAM and HEX, and the PL-HEX transition. For BCC phase, shear-induced melting was found.更多还原