Europhys. Lett.
Volume 68, Number 2, October 2004
Page(s) 219 - 225
Section Condensed matter: structure, mechanical and thermal properties
Published online 01 October 2004
Europhys. Lett., 68 (2), pp. 219-225 (2004)
DOI: 10.1209/epl/i2004-10242-2

Mobile nanoparticles and their effect on phase separation dynamics in thin-film polymer blends

H.-J. Chung, A. Taubert, R. D. Deshmukh and R. J. Composto

Department of Materials Science and Engineering and Laboratory for Research on the Structure of Matter, University of Pennsylvania Philadelphia, PA 19104-6272, USA

received 7 June 2004; accepted in final form 30 August 2004

We present a systematic study of mobile nanoparticles (NP) and their effect on phase separation dynamics in polymer blend films. Starting with a homogeneous dispersion of silica NP in $\tx{PMMA}:\tx{SAN}$ films, the NP are observed to partition into the PMMA-rich phase and stratify during phase separation. The correlation length $\xi$ between phases grows as $\xi\sim t^{1/3}$ for blends containing 0, 2, and 5 $\un{wt}$% NP. However, phase size decreases as the wt% of NP increases. This behavior agrees with a coalescence model, which incorporates an increase in viscosity due to the NP.

64.70.Ja - Liquid-liquid transitions.
82.35.Np - Nanoparticles in polymers.
68.55.-a - Thin film structure and morphology.

© EDP Sciences 2004