Tuning the Relaxation of Nanopatterned Polymer Films with Polymer-Grafted Nanoparticles: Observation of Entropy–Enthalpy Compensation

Published

November 6, 2018

Author(s)

Jack F. Douglas, Xiaoteng Wang, Sonal Bhadauriya, Ren Zhang, Praveen Pitliya, Dharmaraj Raghavan, Alamgir Karim

Abstract

We show that the previously observed polymeric clustering of nanoparticles (NPs) with grafted chains within polymer matrices can be pattern-directed by nanoimprinting ultrathin nanocomposite films so that the NPs segregate to thicker film regions where they are less confined. In particular, we investigate nanoimprinted thin polystyrene (PS) nanocomposite films having an initial thickness h0  90 nm containing PS-grafted titanium dioxide (PS-g-TiO¬2) NPs. We quantify the partitioning of the polymer-grafted nanoparticles (PGNPs) to the patterned regions and show that this PGNP partitioning is due to the same entropic driving force, as observed in our previous work on non-associating PGNPs in nanoimprinted polymer films. This form of pattern-directed self-assembly can be expected to yield films with enhanced and anisotropic optical, electronic and other material properties associated with NP organization into precise large-scale patterns.

Citation

Nano Letters

Pub Type

Journals

Keywords

"polymer-grafted nanoparticles", "nanoparticle association", "pattern-directed assembly" confinement, entropy, dewetting, "nanoimprinted polymer films"

Citation

Douglas, J. , Wang, X. , Bhadauriya, S. , Zhang, R. , Pitliya, P. , Raghavan, D. and Karim, A. (2018), Tuning the Relaxation of Nanopatterned Polymer Films with Polymer-Grafted Nanoparticles: Observation of Entropy–Enthalpy Compensation, Nano Letters (Accessed October 10, 2025)