Saturday, 25 June 2016

Concentration dependent structure of poly(styrene-b-ethylene-alt-propylene) in 1-phenyldodecane

Published Date
19 August 2016, Vol.98:39–44, doi:10.1016/j.polymer.2016.06.008

Title

Concentration dependent structure of poly(styrene-b-ethylene-alt-propylene) in 1-phenyldodecane

Author

Marcel Ockhoma Tapa

Soo-Hyung Choi^,

Department of Chemical Engineering, Hongik University, Seoul 04066, Republic of Korea

Received 14 January 2016. Revised 22 May 2016. Accepted 1 June 2016. Available online 3 June 2016.

Highlights

•
Structure of block copolymer solution in a nearly neutral solvent is investigated using small-angle X-ray scattering (SAXS).
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The nearly neutral solvent mainly attenuates the incompatibility between the two blocks.
•
Slight selective nature of the solvent leads to uneven solvent distribution on the two domains.
•
Intensive SAXS analysis reveals quantitative estimate of averaged solvent distribution.

Abstract

The concentration and temperature dependence of the structure formed by poly(styrene-b-ethylene-alt-propylene) (PS-PEP) diblock copolymer in 1-phenyldodecane, a nearly neutral solvent, was studied using small-angle X-ray scattering (SAXS). As the polymer concentration decreases from 100 wt% to 10 wt%, PS-PEP (M_n,_PS = 42,000 g/mol, M_n,_PEP = 62,000 g/mol, M_w/M_n = 1.04) solutions form lamellae, hexagonally packed cylinders, and disordered structure. The results show that the neutral solvent mainly attenuates the unfavorable interaction between PS and PEP blocks, and thus reduces the domain spacing. The slight selective nature of the solvent, however, leads to uneven solvent distribution on the two domains. In particular, SAXS analysis equipped with the form factor fitting results in quantitative estimate of averaged solvent composition in micro-phase separated domains.