title: Surface Segregation and Bulk Aggregation in an Athermal Thin Film of Polymer-Nanoparticle Blends: Strategies of Controlling Phase Behavior.
abstract: The phase behavior of an athermal film of a polymer-nanoparticle blend (PNB) driven by depletion attraction is investigated by dissipative particle dynamics for nanospheres and nanocubes. Surface segregation is observed at low nanoparticle concentrations, while bulk aggregation is seen at high concentrations. Surface excess and the aggregation number can be controlled by tuning the nanoparticle concentration. As surface-roughened or polymer-grafted nanoparticles are used, uniform PNBs are acquired due to the lack of depletion. Thus, addition of surface-roughened nanoparticles into PNBs of smooth nanoparticles can be employed to tune the phase characteristics. It is found that bulk aggregation is suppressed for both polymer-nanosphere and polymer-nanocube blends. However, surface segregation is impeded for polymer-nanosphere blend but enhanced for polymer-nanocube blend owing to the distinct influence of the nanoparticle shape on depletion.
authors.affiliation: Department of Chemical Engineering, National Taiwan University , Taipei 106, Taiwan.
authors.forename: Chih-Yu
authors.initials: CY
authors.lastname: Teng
authors.affiliation: Department of Chemical Engineering, National Taiwan University , Taipei 106, Taiwan.
authors.forename: Yu-Jane
authors.identifier: 0000-0002-3031-8920
authors.initials: YJ
authors.lastname: Sheng
authors.affiliation: Department of Chemical and Materials Engineering, Department of Physics, National Central University , Jhongli 320, Taiwan.
authors.forename: Heng-Kwong
authors.identifier: 0000-0001-6415-8657
authors.initials: HK
authors.lastname: Tsao