Multimicrometer Noncovalent Monolayer Domains on Layered Materials through Thermally Controlled Langmuir–Schaefer Conversion for Noncovalent 2D Functionalization

Abstract

As functionalized 2D materials are incorporated into hybrid materials, ensuring large-area structural control in noncovalently adsorbed films becomes increasingly important. Noncovalent functionalization avoids disrupting electronic structure in 2D materials; however, relatively weak molecular interactions in such monolayers typically reduce stability toward solution processing and other common material handling conditions. Here, we find that controlling substrate temperature during Langmuir-Schaefer conversion of a standing phase monolayer of diynoic amphiphiles on water to a horizontally oriented monolayer on a 2D substrate routinely produces multimicrometer domains, at least an order of magnitude larger than those typically achieved through drop-casting. Following polymerization, these highly ordered monolayers retain their structures during vigorous washing with solvents including water, ethanol, tetrahydrofuran, and toluene. These findings point to a convenient and broadly applicable strategy for noncovalent functionalization of 2D materials in applications that require large-area structural control, for instance, to minimize desorption at defects during subsequent solution processing.

Oleylamine Impurities Regulate Temperature-Dependent Hierarchical Assembly of Ultranarrow Gold Nanowires on Biotemplated Interfaces

“…Striped phospholipid surfaces − on highly ordered pyrolytic graphite (HOPG, Figure ) provide a useful templating mechanism for controlling assembly of OLAm-capped AuNWs, of particular relevance to examining thermal impacts of trans and saturated chains in OLAm blends. Striped phases of functional alkanes ( e.g.…”

1-nm-Wide Hydrated Dipole Arrays Regulate AuNW Assembly on Striped Monolayers in Nonpolar Solvent

“…AuNW Synthesis and Assembly on Striped diyne PE Templates Striped templates of diyne PE were prepared via Langmuir-Schaefer (LS) conversion 26,28,35,36,38,40 with a thermally regulated transfer stage we have reported previously 38 to achieve templates with typical ordered domain edge lengths > 1 mm. The modeled edge-to-edge distance for the lamellar assembly was 6.8 nm (Figure 2A).…”

“…[26][27][28][29][30][31][32] Photopolymerization of the diyne produces an ene-yne polymer backbone, which has been extensively examined in the context of molecular electronics, 27,28,33 but also stabilizes the monolayer against solvent exchange. 10, [34][35][36][37][38] Recently, we found that in striped monolayers of diyne phospholipids (e.g., 1,2bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphoethanolamine [diyne PE]; Figure 1A), the terminal ammonium functional group protrudes slightly from the surface, forming a ''sitting'' geometry (Figure 1B). 35 This protrusion means that the phosphateammonium zwitterionic pair in the headgroup can adopt a variety of orientations, with stripes of headgroups along the lamellae representing orientable 1D dipole arrays.…”

“…Aligned molecular domains can be >10 mm in edge length depending on molecular structure and monolayer preparation methods. 38,39 Such arrays suggest the possibility of controlled interactions with inorganic nanostructures in the environment, particularly in polarizing anisotropic structures such as wires to impact orientation and alignment at an interface.…”

Lipids: An Atomic Toolkit for the Endless Frontier

“…Although lipid striped phases have classically been studied at small scales ( e.g ., typical STM image edge length <100 nm, as in Figure , upper right), we find it is possible to extend ordering to much longer scales (Figure , upper right panel), , opening the door to technological applications of these high-resolution functional environments. Thermally controlled Langmuir–Schaefer transfer (Figure , upper right panel, left schematic) can, for some molecules, routinely produce striped lipid domains >100 μm 2 , and a recent rotary transfer prototype can produce individual domains with edge lengths up to 100 μm . Microcontact printing (Figure , upper right panel, right schematic) can also be used to generate geometrically controlled microscopic areas of striped phases, although individual ordered domains within the printed area are typically substantially smaller. , Using this approach, we have demonstrated patterning of relatively complex headgroup chemistries, including formation of 1 nm-wide stripes of carbohydrates (phosphoinositol), a simple form of ligand clustering relevant to interactions with cells.…”