Surface characterization of functional poly(diacetylene) and poly(butadiene) mono- and multilayers

Abstract

Abstract:The surface properties of Langmuir-Blodgett mono-and multilayers of a variety of amphiphilic poly(diacetylene)s and poly(butadiene)s were investigated by contact angle, streaming potential <, ellipsometry, and X-ray photoelectron spectroscopic (XPS) measurements. Captive air and octane angles varied between approximately 60 ~ and 105 ~ for hydrophobic x-layers and 31 ~ to 46 ~ for hydrophilic surfaces depending on the particular head group, whereas advancing angles determined via the vertical plate method are considerably higher. Negative streaming potentials were obtained for all surfaces. Positively charged monolayers yielded less negative ~-potential values (-28 mV) than negatively charged (-52 mV) or hydrophobic (-50 mV) layers. Ellipsometry measurements yielded an average layer thickness of 27 ---6 }l for 3 to 11 layers. X-ray photoelectron spectroscopy results qualitatively confirmed the expected composition. All of the samples, which were handled and stored in air after deposition and polymerization, were surface oxidized.

Modification of low-density polyethylene film using polymerizable surfactants

“…While the absolute values of these thicknesses must be regarded as approximate due to an-isotropic and adsorption effects,31,32 these numbers, nonetheless, compare reasonably well with monolayer thicknesses reported for closely related poly(diacetylenes) prepared via Langmuir-Blodgett deposition. 32 In preliminary experiments, the use of purified vesicle dispersions of 1 and 2b (gel filtration through Sephadex G-50, where void volume fractions were employed) gave identical loadings on PE as compared with nonfiltered samples. These results suggest that the vesicles themselves, and not unassociated or micellar monomers, serve as the source of lipid for surface modification.…”

“…Subsequent extraction with CHC13, followed by drying of the organic layer over MgS04 and concentration under reduced pressure, afforded crude 4. Purification by chromatography (silica gel, 9:1 CHCl3-CHjOH) furnished 0.33 g (17%) of 4: NMR (CDC13) 8 1.3 (br s, 32 H, CH2), 1.93 (m, 6 H, CH3C=), 3.6-4.4 (m, 4 H, CH20), 4.1 (t, 4 H, CH2OCO), 5.5 (m, 2 H, vinyl), 6.03 (m, 2 H, vinyl); IR (neat) pq=o 1715, pc=c 1630 cm'1. Anal.…”