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, that control interfacial wetting, reactivity, and adsorption of flexible, ultranarrow inorganic 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 controlling surface chemistry well below the length scale of heterogeneity in an amorphous material.directing effects in further assembly at the interface -recently, we have demonstrated that 1-nm-wide patterns of headgroup dipoles in striped phases on HOPG direct assembly of flexible, ultranarrow gold nanowires (AuNWs) with high precision. 23 In this work, we show that striped PDA films on HOPG can be covalently transferred to polydimethylsiloxane (PDMS), an elastomer common in wearable electronics, 24 microfluidics, 25 cell culture, 26 and soft robotics, 27 using the hydrosilylation reaction that is the basis for the PDMS curing process. This polydiacetylene-on-amorphous material transfer (PATRN) process creates 1-nm-wide functional patterns on the PDMS surface, which generate spatially resolved interactions with the environment (assembly of long, flexible inorganic nanowires, wetting with solvents, interactions with ions), and resist engulfment, a common problem with surface functionalization of PDMS. 28

Microcontact printing can be used to generate well-defined microscopic areas of striped phases of both single-chain and dual-chain amphiphiles.

Promoting, structuring, or limiting adsorption of polyelectrolytes at interfaces is of importance in applications ranging from biomedical devices to nanoscale electronics. Routes for surface functionalization, particularly those capable of controlling the molecular conformation of adsorbates, are typically highly customized for the substrate and must therefore be redeveloped for each application. Here, we show that polymerized diacetylene striped phases with embedded 1 nm resolution functional patterns control polyelectrolyte adsorption on a crystalline inorganic surface (graphite) and can be easily transferred to elastomeric materials (here, poly(dimethylsiloxane), PDMS) to control adsorption on amorphous surfaces as well. We demonstrate that transferred functional poly(diacetylene) layers on PDMS can be designed to promote adsorption of polyelectrolytes or to limit protein adsorption, two common goals in controlling PDMS surface chemistry for biomedical applications.