Gradient and Patterned Polymer Brushes via a Polymer-Single-Crystal-Assisted-Grafting-to Approach

Polymer brushes have been a focus in polymer research due to its potential to tune surface properties and provide a platform to study the tethered chain behavior. Gradient and patterned polymer brushes are of particular interest because they provide a spatially control over the chemical/ physical characteristics of the brush that can be used to systematically study surface structure-property relationship in one simple experiment. In this study, we present a new method to fabricate gradient and patterned polymer brush with predetermined and precisely controlled chain density gradient. Here, a newly discovered self-assembly-assisted-grafting-to approach is utilized where end-functionalized polymers are pre-assembled into two-dimensional polymer single crystals which can be coupled to flat surface to form polymer brushes. Co-crystallization has been utilized to obtain gradient brushes with precisely pre-determined grafting density and gradient pattern. Crystallization behaviors of the gradient brushes have also been systematically investigated.