嵌段共聚物受限于软孔内的自组装

Phase diagram of diblock copolymer confined in a cylindrical nanopore with polymer-grafted surface

利用自洽场方法研究两嵌段共聚物受限于接枝均聚物链(聚合物刷)圆孔中的自组装相形貌.研究表明,当圆孔内径一定时,嵌段比f和聚合物刷C的体积分数■是调控嵌段共聚物相形貌的主要因素,聚合物刷的弹性熵也起着重要作用.当f=0.7时,在聚合物刷的浸润下,贴近刷表面处AB嵌段共聚物构成环层状结构,随着■的减小这种结构会周而复始地出现.当f处于0.3—0.7之间的非对称状态时,体系易形成外环内柱的相结构.当f=0.35时,体系可以出现一种新颖的复杂结构——最内层为柱状结构,次内层为环层状结构,次外层呈环形排列的柱状结构,最外层又是环层状结构,即环柱交替结构.给出了以f和嵌段共聚物体积分数■作为参数空间的嵌段共聚物结构相图.

Using self-consistent field calculation, the new equilibrium morphology of a diblock copolymer melt confined in a brush- covered cylindrical nanopore can be found. The morphology is formed as a function of brush density and A-monomer fraction f. When f = 0.7, due to the wetting effect produced by polymer brush the outside concentric lamellar ring will come up again with increasing ^-φAB. We carefully examined the intermediate phases and discovered a rich variety of new two-dimensional structures that have no analogue in the unconfined system, which include nonhexagonally coordinated cylinder phases and structures intermediate between lamellae and cylinders, like CRCR, when f = 0.35. Then we map the stability regions and phase boundaries for all the structures we found.