Polyion Complex Langmuir−Blodgett Layers Containing an Ionic Water-Soluble Polysilane

Abstract

Monolayers of anionic amphiphiles, arachidic acid (C19COOH) and a double long chain sulfonic acid derivative (2C12SO3Na), were spread on the water subphase containing an ammonium-containing polysilane (APS), and Langmuir−Blodgett (LB) films from these polyion complex monolayers were prepared. Single layer deposition of these polyion complex monolayers was successfully achieved onto a hydrophilic substrate under all conditions examined, but multilayers could be prepared under limited conditions in the Z-type mode. The UV absorption spectra of the transferred C19COO(H)/APS monolayers indicated that the conformational state of APS in the films are dependent on the subphase pH. The absorbance of the transferred LB films confirmed that the APS is incorporated monomolecularly on the lifting process. Polarized UV absorption spectra revealed no preferential orientation of the APS backbone in the LB films. The multilayers formed in the Z-type deposition were eventually inverted to stacked bilayer structure (Y-type layers) after aging and successive annealing, as proven by the small angle X-ray reflectometry. LB films composed of 2C12SO3 -/APS possessed a more refined layer structure with a more smooth surface than those of C19COO(H)/APS, probably due to a better dimensional matching of the APS unit and the cross section of the amphiphile. Finally, structural features of the C19COO(H)/APS polyion complex LB film were discussed in comparison with those of a homologous amphiphilic material reported previously (Seki et al. Macromolecules 1995, 28, 5609).

Preparation and Characterization of Polyion-Complexed Langmuir−Blodgett Films Containing an NLO Chromophore

“…The secondharmonic intensity, however, was found to increase only slightly with a 5-fold increase in the number of deposited layers, and these authors concluded that although deposited as Z-type films, molecular rearrangement to a symmetric structure occurs during the dipping process. Seki et al 25 and Pen ˜acorada et al 29 similarly concluded from X-ray measurements that LB films of polyioncomplexed arachidic acid initially deposited as either Z-type or X-type multilayers invert to Y-type bilayers upon aging.…”

Langmuir Monolayers of Polyion Complexes of Soluble Quaternary Ammonium-Functionalized Azobenzene Chromophores

“…Surface pressure plateaus, like those observed in the compression isotherms of Figure , have been reported for a number of similar polyion-complexed systems 7,9,10,21,26,39 as well as for cellulose derivatives containing covalently attached hydrophobic side chains. , The plateau has been ascribed to a transition from an expanded to a condensed monolayer, , a fluid−solid transition, the formation of a discrete bilayer, the nonspecific removal of material from the surface, or collapse . It is, in fact, probable that the exact nature of the phase transition responsible for the plateau differs for the various systems.…”

Mechanism of High Proton Mobility in the Two-Dimensional Nanospace at the Interlayer of a Multilayer Polymer Nanosheet Film

“…The K a value of acid molecules condensed in two dimensions shifts to the basic side due to the strong electrostatic interaction between the molecules. 23,24 Moreover, the K a value of a monolayer can be determined by the dependence of the molecular area of the monolayer on the subphase pH. 25 To obtain the pK a value of the p(DDA/AA49) monolayer, the copolymer was spread on water subphases with The film was prepared using the p(DDA/AA49) copolymer for subphase pH 5.9, 7.0, and 10 and the p(DDA/AA47) copolymer for subphase pH 7.9 and 9.1.…”