title: Fluorocarbon crowning: Langmuir-Blodgett deposition versus self-assembly at molecularly rough surfaces.
abstract: Langmuir-Blodgett deposition of a single monolayer of 1,2,4,5-tetrakis[(N-(perfluoroundecanoamidoethyl)-N,N-dimethylammonium)methyl]benzene tetrabromide (1) onto a thin film made from alternating layers of poly(diallydimethylammonium chloride) (PDADMA) and poly(4-styrenesulfonate) (PSS) ions affords a uniform fluorinated surface of low energy. An analogous surface that has been constructed by self-assembly shows the same critical surface tension of 16.5 dyn/cm. A comparison of Zisman plots for these two modified films, in combination with analysis by X-ray photoelectron spectroscopy, indicates that Langmuir-Blodgett deposition produces a higher quality and more densely packed fluorocarbon surface that is very hydrophobic. In sharp contrast, the use of a single-chain analog (i.e., N-(perfluoroundecanoamidoethyl)-N,N,N-trimethylammonium bromide) (2)) affords relatively high energy surfaces by Langmuir-Blodgett deposition and by self-assembly.
authors: Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, USA.
authors: Donald H
authors: DH
authors: McCullough
authors: Ruslan
authors: R
authors: Grygorash
authors: Steven L
authors: SL
authors: Regen
mesh_terms: D005466:Fluorocarbons / Q000737:chemistry*; D006842:Hydrocarbons, Brominated / Q000737:chemistry*; D015394:Molecular Structure; D011095:Polyethylenes / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013451:Sulfonic Acids / Q000737:chemistry; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: C523648:1,2,4,5-tetrakis((N-(perfluoroundecanoamidoethyl)-N,N-dimethylammonium)methyl)benzene tetrabromide; D005466:Fluorocarbons; D006842:Hydrocarbons, Brominated; D011095:Polyethylenes; D011108:Polymers; D000644:Quaternary Ammonium Compounds; D013451:Sulfonic Acids; D013501:Surface-Active Agents; C041004:poly-N,N-dimethyl-N,N-diallylammonium chloride; C077114:styrenesulfonic acid polymer