Terraced and Smooth Gradient Polymer Brushes via a Polymer Single‐Crystal Assisted Grafting‐To Method

Gradient polymer brushes provide a spatial gradient change in molecular characteristics of the brush, and such a change can be utilized to study structure–property relationships in a combinatorial fashion. In this study, a bottom‐up method was used to synthesize gradient polymer brushes with a predesigned and precisely controlled grafting density gradient and brush pattern. A polymer single‐crystal assisted grafting‐to (PSCAGT) method was employed where end‐functionalized polymers were grown into two‐dimensional polymer single crystals. The latter were chemically coupled to a solid substrate to form well‐defined polymer brushes. To tune the grafting density, end‐dissimilar polymers were used to co‐crystallize into one single crystal. Programmed single‐crystal growth was introduced to synthesize brushes with two different gradient architectures, that is, terraced and smooth gradient with pyramid patterns. This work demonstrates that the PSCAGT method offers a unique means to tune polymer brush nanostructure. A facile bottom‐up method was developed to synthesize patterned gradient polymer brushes with precisely controlled grafting density and gradient architecture. Both terraced and smooth gradient brushes were synthesized with tunable gradient slopes.