The use of scanning polarization force microscopy to study the miscibility of a molecular wire candidate and an insulating fatty acid in mixed LB films
- 9 May 2008
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Soft Matter
- Vol. 4 (7), 1508-1514
- https://doi.org/10.1039/b716798a
Abstract
Mixed films containing a conjugated “molecular wire” candidate and an “insulating” fatty acid have been prepared by the Langmuir–Blodgett technique. Specifically, this paper reports the fabrication of mixed films as well as miscibility studies of 4-[4-(4-hexyloxyphenylethynyl)phenylethynyl]benzoic acid (HBPEB) and docosanoic (or behenic) acid (BA). Surface pressure vs. area per molecule isotherms were recorded, with excess area and excess Gibbs energy of mixing calculated. Surface potential-area per molecule isotherms were also recorded for mixtures over the whole range of mole fractions, with negative deviations from the additivity rule revealing orientational changes induced in the HBPEB molecules. The Langmuir films were transferred onto solid supports and characterized by SPM techniques, with atomic force microscopy (AFM) revealing that well-ordered, defect-free films are obtained. The use of scanning polarization force microscopy (SPFM), which provides non-contact imaging based on differences in surface charge distribution, i.e., surface potential, provides complimentary information regarding distribution of the components within the mixed films. From the comprehensive miscibility study performed, which includes thermodynamic and imaging methods, it can be concluded that the wire-like molecule and the fatty acid are miscible over the 0–0.1 and 0.8–1 ranges of HBPEB mole fraction while phase separation occurs for HBPEB mole fractions over the 0.1–0.8 range.Keywords
This publication has 57 references indexed in Scilit:
- Designing bistable [2]rotaxanes for molecular electronic devicesPhilosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2007
- Synthesis and Structure of PAEsPublished by Springer Science and Business Media LLC ,2005
- Electrical Measurements in Molecular ElectronicsChemistry of Materials, 2004
- Optical Characterization of Oligo(phenylene−ethynylene) Self-Assembled Monolayers on GoldThe Journal of Physical Chemistry B, 2004
- Conformational Changes of Single Molecules Induced by Scanning Tunneling Microscopy Manipulation: A Route to Molecular SwitchingPhysical Review Letters, 2001
- Dynamics of Photoinduced Charge Separation and Charge Recombination in Synthetic DNA Hairpins with Stilbenedicarboxamide LinkersJournal of the American Chemical Society, 2000
- Evidence of Aggregate Formation for 2,5-Dialkylpoly(p-phenyleneethynylenes) in Solution and Thin FilmsMacromolecules, 1998
- Scanning Polarization Force Microscopy Study of the Condensation and Wetting Properties of Glycerol on MicaThe Journal of Physical Chemistry B, 1998
- Individual single-wall carbon nanotubes as quantum wiresNature, 1997
- Are Single Molecular Wires Conducting?Science, 1996