An XPS study of the surface–bulk compositional differences in siloxane‐containing block copolymers and polymer blends

Abstract

SYNOPSISX-ray photoelectron spectroscopy (XPS) is used to compare the surface behavior in various binary systems of poly (dimethylsiloxane) with poly( bisphenol A sulfone) and poly-(bisphenol A carbonate). All the systems studied show a pronounced surface enrichment in siloxane. At a fixed siloxane concentration in the bulk the lowest extent of surface enrichment is observed in the neat copolymers, next go the blends of copolymers in homopolymers, and the highest extent of surface enrichment is characteristic of the blends of homopolymers. The blends of two copolymers show an unexpected surface behavior: The addition of minor amounts of a siloxane-rich copolymer to another copolymer possessing a much lower siloxane content decreases (rather than increases) the surface siloxane concentration of the latter. A microscopic model is suggested to explain the observed surface behavior. The model involves the formation of a "quasi-two-dimensional" overlayer of additive's macromolecules on the blend surface, with the macromolecules oriented preferentially parallel to the sample surface.

Surface orientation of hydrophilic groups in sulfonated poly(ether ether ketone) membranes

“…He suggested that the differences in the surface free energy of various components within a polymer membrane may dominate the overall surface morphology, whereby the lower surface energy segment resided near the polymer-air interface [16,17,[48][49][50].…”

Surface segregation of components in poly(vinyl chloride)-polydimethylsiloxane and polystyrene-poly(propylene oxide) solvent-cast blends

“…6 The quantitative surface analysis of the PPO-PS decreases substantially with increasing MW of the siloxane additive. In 1% blends, for example, blends was made based on the resolution of the Cls spectra into contributions due to the ether the coverage of the blend surface with siloxane drops from about 100 to 50% when the PDMS carbon atom of PPO (E b Å 286.6 eV) and all other carbon atoms (E b Å 285.0 eV).…”

Dendrimer-Stabilized Ru Nanoparticles Immobilized in Organo-Silica Materials for Hydrogenation of Phenols

“…Herein the sol-gel method allows diffusion limitations to be avoided, inevitable, when bulky dendrimer or dendron is anchored to the surface of ready carrier [64][65][66][67][68][69]. The materials obtained were characterized by infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS) and solid-state nuclear magnetic resonance (NMR) spectroscopy, that confirmed the presence in their structures of fragments, inherent in the SiO 2 bulk support [74,75] [76][77][78][79][80].…”

“…Microporous dendr-G3-SiO2 (Figure 2 The materials obtained were characterized by infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS) and solid-state nuclear magnetic resonance (NMR) spectroscopy, that confirmed the presence in their structures of fragments, inherent in the SiO2 bulk support [74,75], PPI dendrimers (NCH2CH2CH2N, NCH2CH2CH2NH2, etc.) [76] and modifying groups, that link the former two residues, include epoxide-opening products of the former glycidyl groups (SiCH2CH2CH2O, OCH2CH(OH)CH2NH) [76][77][78][79][80].…”