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

Lamellar phases of alkyldiacetylenes in which the alkyl chains lie parallel to the substrate represent a straightforward means for scalable 1‐nm‐resolution interfacial patterning. This capability has the potential for substantial impacts in nanoscale electronics, energy conversion, and biomaterials design. Polymerization is required to set the 1‐nm functional patterns embedded in the monolayer, making it important to understand structure–function relationships for these on‐surface reactions. Polymerization can be observed for certain monomers at the single‐polymer scale using scanning probe microscopy. However, substantial restrictions on the systems that can be effectively characterized have limited utility. Here, using a new multi‐scale approach, we identify a large, previously unreported difference in polymerization efficiency between the two most widely used commercial diynoic acids. We further identify a core design principle for maximizing polymerization efficiency in these on‐surface reactions, generating a new monomer that also exhibits enhanced polymerization efficiency.

Nanocrystals are often synthesized using technical grade reagents such as oleylamine (OLAm), which contains a blend of 9-cis-octadeceneamine with trans-unsaturated and saturated amines. Here, we show that gold nanowires (AuNWs) synthesized with OLAm ligands undergo thermal transitions in interfacial assembly (ribbon vs. nematic); transition temperatures vary widely with the batch of OLAm used for synthesis. Mass spectra reveal that higher-temperature AuNW assembly transitions are correlated with an increased abundance of trans and saturated chains in certain blends. DSC thermograms show that both pure (synthesized) and technical-grade OLAm have primary melting transitions near −5 °C (20–30 °C lower than the literature melting temperature range of OLAm). A second, broader melting transition (in the previous reported melting range) appears in technical grade blends; its temperature varies with the abundance of trans and saturated chains. Our findings illustrate that, similar to biological membranes, blends of alkyl chains can be used to generate mesoscopic hierarchical nanocrystal assembly, particularly at interfaces that further modulate transition temperatures.

Most high-resolution interfacial patterning approaches are restricted to crystalline inorganic interfaces. Recently, we have shown that it is possible to generate 1 nm resolution functional patterns on soft materials, such as polydimethylsiloxane (PDMS), by creating highly structured striped patterns of functional alkyldiacetylenes on a hard crystalline surface, photopolymerizing to set the molecular pattern as a striped-phase polydiacetylene (sPDA), and then covalently transferring the sPDAs to PDMS. Transfer depends on the diacetylene polymerization, making it important to understand design principles for efficient sPDA polymerization and cross-linking to PDMS. Here, we combine single-molecule and fluorescence-based metrics for sPDA polymerization and transfer, first to characterize sPDA polymerization of amine striped phases, and then to develop a probabilistic model that describes the transfer process in terms of sPDA–PDMS cross-linking reaction efficiency and number of reactions required for transfer. We illustrate that transferred patterns of alkylamines can be used to direct both adsorption of CdSe nanocrystals with alkyl ligand shells and covalent reactions with fluorescent dyes, highlighting the utility of functional patterning of the PDMS surface.

The evolution of lipids in nanoscience exemplifies the powerful coupling of advances in science and technology. Here, we describe two waves of discovery and innovation in lipid materials: one historical and one still building. The first wave leveraged the relatively simple capability for lipids to orient at interfaces, building layers of functional groups. This simple form of building with atoms yielded a stunning range of technologies: lubricant additives that dramatically extended machine lifetimes, molecules that enabled selective ore extraction in mining, and soaps that improved human health. It also set the stage for many areas of modern nanoscience. The second wave of lipid materials, still growing, uses the more complex toolkits lipids offer for building with atoms, including controlling atomic environment to control function (e.g., pK a tuning) and the generation of more arbitrary two-dimensional and three-dimensional structures, including lipid nanoparticles for COVID-19 mRNA vaccines.