Molecular simulation of 2-dimensional microphase separation of single-component homopolymers grafted onto a planar substrate

¹ Japan Science and Technology Agency (JST), Exploratory Research for Advanced Technology (ERATO), Takahara Soft Interfaces Project, Kyushu University - 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
² Institute for Materials Chemistry and Engineering, Kyushu University (IMCE), Kyushu University 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
³ International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan

Received: 20 September 2012
Accepted: 11 December 2012

Abstract

The structural phase behavior of polymer brushes, single-component linear homopolymers grafted onto a planar substrate, is studied using the molecular Monte Carlo method in 3 dimensions. When simulation parameters of the system are set in regions of macrophase separation of solution for the corresponding non-grafted homopolymers, the grafted polymers also prefer segregation. However, macrophase separation is disallowed due to the spatially fixed grafting points of the polymers. Such constraints on the grafting are similar to connecting points between blocks of non-grafted diblock copolymers at the microphase separation in the melt state. This results in “microphase separation” of the homopolymer brush in the lateral direction of the substrate. Here we extensively search the parameter space and reveal various lateral domain patterns that are similar to those found in diblock copolymer melts at microphase separation.