Eur. Phys. J. E (2003) 11: 111-115
https://doi.org/10.1140/epje/i2003-10010-2

Depletion effect on partial organization of atactic polymer chain segments in microcells

¹ Department of Polymer Science and Engineering, Chemistry Building, Nanjing University, Nanjing 210093, PRC
² The State Key Laboratory of Polymer Physics and Chemistry at Changchun, Changchun 130022, PRC

^* e-mail: xuegi@nju.edu.cn
^** e-mail: zqwang@nju.edu.cn

Received: 10 April 2003
Published online: 11 June 2003

Abstract

Glass transition for atactic poly(methyl methacrylate) (a-PMMA) prepared in nano-cells by microemulsion polymerization was measured at a faster heating rate after slow cooling of the sample from a temperature above T _g. An additional enthalpy relaxation and glass transition were observed at higher temperatures for the a-PMMA sample due to the partial organization of the chain segments which occurred during microemulsion polymerization. The re-precipitated a-PMMA did not show any self-organization under the same thermal conditions, although there are no changes in molecular weight or tacticity of the polymer chains. A depletion-interaction phenomenon was understood to provide entropic force for the self-organization of polymer chains inside the walls of the microemulsion cells.