Issue 42, 2016

Is kinetic polymer arrest very specific to multiwalled carbon nanotubes?

Abstract

In this study we have assessed, using dielectric relaxation spectroscopy (DRS), the confinement effects of the more mobile chain in partially miscible polymeric blends of PS/PVME (polystyrene/poly(vinyl methyl ether)) in the presence of anisotropically shaped MWCNTs (multiwalled carbon nanotubes). To understand if this confinement effect is very specific to MWCNTs, the characteristic dimensions of which are often close to the radius of gyration of the polymeric chains, a few other particles like spherical silver, stacked clay tactoids and platy graphene sheets at similar weight fractions were also incorporated and systematically studied. The DRS studies reveal that the more mobile chain (here PVME) experiences possibly two different environments in the presence of frozen PS and more importantly in the presence of MWCNTs at temperatures close to and not so far from the blend Tg. The presence of bimodal relaxations with a weak temperature independent faster relaxation in the blends is composition dependent (PS rich blends). Assuming that there are no chemical interactions of PVME with the particles, these confinement effects seem to be very specific to MWCNTs as the bimodal relaxations were completely absent in the case of other nanoparticles. In the case of polymer blends, when two different chains are brought together, a loss in the deformational entropy is expected due to the excluded volume interaction and chain connectivity effects. In the presence of nanoparticles, especially MWCNTs, the polymer coils are subjected to perturbation leading to entropic loss in the system, which determine the miscibility in the blends. The configurational entropy near glass transition was assessed to understand the improved miscibility due to MWCNTs in this particular blend. The length of cooperativity suggests a cooperative motion of PS and PVME over shorter length scales in the case of MWCNTs as compared to other particles. This also hints at perturbed PVME motion in the network of MWCNTs. Taken together, our study reveals that the kinetic PVME arrest results in two different environments and is dependent on the effective concentration of MWCNTs in the blends.

Graphical abstract: Is kinetic polymer arrest very specific to multiwalled carbon nanotubes?

Supplementary files

Article information

Article type
Paper
Submitted
20 Jun 2016
Accepted
19 Sep 2016
First published
23 Sep 2016

Phys. Chem. Chem. Phys., 2016,18, 29226-29238

Is kinetic polymer arrest very specific to multiwalled carbon nanotubes?

P. Xavier, K. M. Nair, L. K. and S. Bose, Phys. Chem. Chem. Phys., 2016, 18, 29226 DOI: 10.1039/C6CP04303H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements