Abstract
Bioinspired membrane molecules with improved physical properties and enhanced stability can serve as functional models for conventional lipid or amphiphilic species. Importantly, these molecules can also provide new insights into emergent phenomena that manifest during self-assembly at interfaces. Here, we elucidate the structural response and mechanistic steps underlying the self-assembly of the amphiphilic, charged oligodimethylsiloxane imidazolium cation (ODMS-MIM+) at the air-aqueous interface using Langmuir trough methods with coincident surface-specific vibrational sum-frequency generation (SFG) spectroscopy. We find evidence for a new compression-induced desolvation step that precedes commonly known disordered-to-ordered phase transitions to form nanoscopic assemblies. The experimental data was supported by atomistic molecular dynamics (MD) simulations to provide a detailed mechanistic picture underlying the assembly and the role of water in these phase transitions. The sensitivity of the hydrophobic ODMS tail conformations to compression─owing to distinct water-ODMS interactions and tail-tail solvation properties─offers new strategies for the design of interfaces that can be further used to develop soft-matter electronics and low-dimensional materials using physical and chemical controls.
| Original language | English |
|---|---|
| Pages (from-to) | 2273-2280 |
| Number of pages | 8 |
| Journal | Journal of Physical Chemistry Letters |
| Volume | 13 |
| Issue number | 10 |
| DOIs | |
| State | Published - Mar 17 2022 |
Funding
ODMS-MIM+ oligomer synthesis, molecular dynamics calculations, and manuscript preparation were performed at the Center for Nanophase Materials Sciences, which is a U.S. DOE Office of Science User Facility. SFG measurements and analysis, and manuscript preparation were supported by the U.S. DOE, Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division, and Materials Sciences and Engineering Division. A portion of this research used resources at the Spallation Neutron Source, a U.S. DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. This research used resources of the Oak Ridge Leadership Computing Facility, which is a U.S. DOE Office of Science User Facility.