Designing Interfacial Reactions for Nanometer-Scale Surface Patterning of PDMS with Controlled Elastic Modulus

Abstract

Control over the surface chemistry of elastomers such as polydimethylsiloxane (PDMS) is important for many applications. However, achieving nanostructured chemical control on amorphous material interfaces below the length scale of substrate heterogeneity is not straightforward, and can be particularly difficult to decouple from changes in network structure that are required for certain applications (e.g., variation of elastic modulus for cell culture). We have recently reported a new method for precisely structured surface functionalization of PDMS and other soft materials, which displays high densities of ligands directly on the material surface, maximizing steric accessibility. Here, we systematically examine structural factors in the PDMS components (e.g., base and cross-linker structures) that impact efficiency of the interfacial reaction that leads to surface functionalization. Applying this understanding, we demonstrate routes for generating equivalent nanometer-scale functional patterns on PDMS with elastic moduli from 0.013 to 1.4 MPa, establishing a foundation for use in applications such as cell culture.

Inkjet Printing of Nanoscale Functional Patterns on 2D Crystalline Materials and Transfer to Soft Materials

“…Previously, we have shown that the sPDA layers on HOPG can be transferred to soft materials including PDMS ,− and hydrogels, , taking advantage of the cross-linking reactions used to solidify the bulk polymer (Figure a). For instance, in polyacrylamide (PAAm) hydrogel cross-linking, the free radical polymerization reaction can utilize the PDA as a reactant, which creates a covalent linkage between the PAAm and the sPDA layer.…”