Width of homopolymer interfaces in the presence of symmetric diblock copolymers

Abstract

The interface between polystyrene and poly(methy1 methacrylate) homopolymers was investigated as a function of the concentration of added symmetric diblock copolymer of PS and PMMA, denoted P(S-b-MMA), using neutron reflectivity. It was found that as the number of P(S-b-MMA) chains added to the interface between PS and PMMA was increased, the width of the gradient between the PS and PMMA segments broadened. In particular, the width of the interface between PS and PMMA homopolymers is 50 A and, with the addition of P(S-b-MMA), increases to -85 A. At an amount corresponding to approximately half the thickness of the lamellar microdomain periodicity in the bulk, the interface becomes saturated with the copolymer. Further addition of copolymer chains to the interface results in a marked increase in the off-specular scattering, which is associated with either an ordering of the copolymer chains at the interface or an increase in the curvature of the interface. Studies were also performed on mixtures of homopolymers and copolymers. Here, the interface between the lamellar microdomains of the P(S-b-MMA) is found to increase from 50 A for the pure copolymer to 75 8, as PS and PMMA homopolymer is added to the copolymer. The broadening of the interface seen in both sets of experiments is due to a significant penetration of the homopolymer into the interfacial region. These results are consistent with the reduction in the interfacial tension between the homopolymers with the addition of the diblock copolymer.

Controlled synthesis of anthracene-labeled -amine polystyrene to be used as a probe for interfacial reaction with mutually reactive PMMA

“…100 nm, i.e., 20 times larger compared to the non-reactive PMMA/PS interface (5 nm). [20] A deeper analysis has been undertaken to clarify this situation and to analyze it in relation to the molecular weight of the reactive precursors. It will be reported in a future publication.…”

Modeling reactive blending: An experimental approach

“…For the PS/PMMA (60/40) reactive blend, if M w of the in situ formed graft copolymer is taken as 100,000 g/mol 10 and the lamellar spacing of the copolymer as 39.8 nm, 11 then eq. (8) reduces to:…”

Kinetics of dispersion of nanoparticles in thin polymer films at high temperature

“…Is it possible to quantify this time evolution of PGNP dispersion at higher temperature, in terms of its diffusivity ? For this purpose we try to model the interface density profiles as an inter-diffusion process of PGNPs across the density gradient similar to earlier reports of inter-diffusion in polymer blends [46][47][48] . For estimating this mobility our reference is the EDP for T1.…”