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

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 system-atically 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.

Automated summary

Controlling the surface chemistry of elastomers, such as PDMS, is crucial for various applications. However, achieving nanostructured chemical control on amorphous material interfaces below the length scale of substrate heterogeneity is not easy, and is particularly challenging to separate from changes in network structure. A new method for precisely structured surface functionalization of soft materials, including PDMS, has been developed, maximizing steric accessibility. This provides a foundation for generating nanometer-scale functional patterns on PDMS with varying elastic moduli, which is important for applications like cell culture.