One Nanometer Wide Functional Patterns with a Sub-10 Nanometer Pitch Transferred to an Amorphous Elastomeric Material.

Decades of work in surface science have established the ability to functionalize clean inorganic surfaces with sub-nm precision, but for many applications, it would be useful to provide similar control over the surface chemistry of amorphous materials such as elastomers. Here, we show that striped monolayers of diyne amphiphiles, assembled on graphite and photopolymerized, can be covalently transferred to polydimethylsiloxane (PDMS), an elastomer common in applications including microfluidics, soft robotics, wearable electronics, and cell culture. This process creates precision polymer films <1 nm thick, with 1 nm wide functional patterns, which control interfacial wetting and reactivity, and template adsorption of flexible, ultranarrow Au nanowires. The polydiacetylenes exhibit polarized fluorescence emission, revealing polymer location, orientation, and environment, and resist engulfment, a common problem in PDMS functionalization. These findings illustrate a route for patterning surface chemistry below the length scale of heterogeneity in an amorphous material.