title: Sitting Phases of Polymerizable Amphiphiles for Controlled Functionalization of Layered Materials.
abstract: Precisely tailoring surface chemistry of layered materials is a growing need for fields ranging from electronics to biology. For many applications, the need for noncovalently adsorbed ligands to simultaneously control interactions with a nonpolar substrate and a polar solvent is a particular challenge. However, biology routinely addresses a similar challenge in the context of the lipid bilayer. While conventional standing phases of phospholipids (such as those found in a bilayer) would not provide spatially ordered interactions with the substrate, here we demonstrate formation of a sitting phase of polymerizable phospholipids, in which the two alkyl chains extend along the surface and the two ionizable functionalities (a phosphate and an amine) sit adjacent to the substrate and project into the solvent, respectively. Interfacial ordering and polymerization are assessed by high-resolution scanning probe measurements. Water contact angle titrations demonstrate interfacial pKa shifts for the lipid phosphate but not for the amine, supporting localization of the phosphate near the nonpolar graphite surface.
authors.affiliation: Department of Chemistry and ‡Weldon School of Biomedical Engineering, Purdue University , West Lafayette, Indiana 47907, United States.
authors.forename: Jae Jin
authors.initials: JJ
authors.lastname: Bang
authors.affiliation: Department of Chemistry and ‡Weldon School of Biomedical Engineering, Purdue University , West Lafayette, Indiana 47907, United States.
authors.forename: Kortney K
authors.initials: KK
authors.lastname: Rupp
authors.affiliation: Department of Chemistry and ‡Weldon School of Biomedical Engineering, Purdue University , West Lafayette, Indiana 47907, United States.
authors.forename: Shane R
authors.initials: SR
authors.lastname: Russell
authors.affiliation: Department of Chemistry and ‡Weldon School of Biomedical Engineering, Purdue University , West Lafayette, Indiana 47907, United States.
authors.forename: Shi Wah
authors.initials: SW
authors.lastname: Choong
authors.affiliation: Department of Chemistry and ‡Weldon School of Biomedical Engineering, Purdue University , West Lafayette, Indiana 47907, United States.
authors.forename: Shelley A
authors.initials: SA
authors.lastname: Claridge