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Entropy-Driven Segregation of Polymer-Grafted Nanoparticles under Confinement



Ren Zhang, Bongjoon Lee, Christopher Stafford, J. F. Douglas, Andrey V. Dobrynin, Michael R. Bockstaller, Alamgir Karim


Polymer-grafted nanoparticles (PGNPs) have attracted much attention due to the enhanced dispersion in polymeric materials via an interacting brush layer that enables unique functionality and stability. The miscibility and organization of nanoparticles within a polymer matrix can be controlled by changing their mutual affinity or through the application of external fields (i.e. electric, magnetic, chemical template or shear stress). In the context of external field driven assembly, soft stamping has the potential to accomplish programmed nanomaterials for optimizing properties of hybrid materials. We present a facile method involving soft topographic patterning of thin films composed of PGNPs in a matrix of the same polymer. This simple strategy provides precise control over PGNP segregation within "programmed" topographic features that renders "visual order" to the nanoparticles. This is achieved through modulation of the conformational entropy of the surface-grafted chains that forces PGNP segregation within the film patterns. The molecular factors responsable for the entropically driven nanoparticle localization are validated by direct measurement of nanoparticle distribution and its time evolution.
Proceedings of the National Academy of Sciences


polymer, blends, nanoparticles, confinement, entropy, phase separation


Zhang, R. , Lee, B. , Stafford, C. , Douglas, J. , Dobrynin, A. , Bockstaller, M. and Karim, A. (2017), Entropy-Driven Segregation of Polymer-Grafted Nanoparticles under Confinement, Proceedings of the National Academy of Sciences, [online], (Accessed July 18, 2024)


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Created February 21, 2017, Updated October 12, 2021