Tuesday, September 15, 2009, 10:00 am — Bldg. 735, conf rm B
The possibility of systematic and controlled variation of the confining length in polymer nanocomposites (PNC), qualifies them as the best candidate to study the thermal and dynamical behavior of polymer in confinement. The confinement parameters for such systems can be varied by changing the inter particle spacing. The interface morphology plays an important role in deciding the thermo - mechanical behavior of such composite systems [1]. Techniques like multi speckle synchrotron XPCS and SAXS are the best experimental platform to directly study the macroscopic behavior from microscopic interaction viewpoints. Here I present the reole of interface morphology in tunning the galss transition of our nanocomposite systems. The dynamical results are presented on Poly methylmethaacrylate (PMMA) capped gold nanoparticles embedded in PMMA matrix and thiol terminated polystyrene (PST) grafted gold nanoparticle as a function of temperature (T), wave vector (q), volume fraction of nanoparticles [2] and the functionality, (f ) respectively [3]. Wave vector dependent non-exponential relaxation of the intermediate scattering functions (ISF) showed the existence of intrinsic length scale for dynamical heterogeneity. By varying the functionality and temperature in similar measurements we found transition from a dynamical arrested state to liquid like relaxation behavior.
References
1. S. Srivastava and J. K. Basu, Phys Rev Lett. 98, 165701 (2007)
2. S. Srivastava, A.K. Kandar, J.K. Basu et al. Phys. Rev. E., 79, 021408 (2009)
3. A.K. Kandar, S. Srivastava, J.K. Basu, et al, J. Chem. Phys, 130, 121102 (2009)
Hosted by: Oleg Gang
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