| 摘要: | 摘要： This paper investigates the film instability and structural evolution of solvent‐annealed polystyrene‐block‐poly(4‐vinylpyridine), P(S‐b‐4VP), as thin films of initially monolayer thickness on bare substrates (SiOx/Si) and substrates coated with end‐grafting PS (PS–SiOx/Si) under tetrahydrofuran vapor. At an early stage of solvent annealing, merging of nanospheres to form nanocylinders produces film rupture, creating small holes within a continuous layer. Because of the connectivity, the coalescence of incipient holes is driven by 2D pressure relaxation. Upon further iterative solvent annealing and drying, flat islands progressively grow outward at the expense of expanding holes until they contact with the edges of holes to form a network‐like cellular structure, and then decay into hemispherical droplets. The capillary driving forces associated with the negative excess interfacial entropy are responsible for the film instability of micelles on PS–SiOx/Si. In contrast, thin P(S‐b‐4VP) films on SiOx/Si reveal only small holes during iterative swelling and drying. The presence of these small holes is ascribed to an incomplete coverage during the merging of nanospheres and the anchoring of P(S‐b‐4VP) chains on SiOx/Si. Adsorption in micellar films has three important effects—retarding the motion of micelles, increasing the film stability, and favoring complete wetting. In the early stages of solvent annealing, the merging of nanospheres to form nanocylinders gives rise to film rupture, creating holes of small size within a continuous layer. Upon further iterative solvent annealing and drying, flat islands progressively grow outward at the expense of expanding hole size until they contact with the edges of holes to form a network‐like cellular structure, and then decay into hemispherical droplets.
其他題名： Macromol. Chem. Phys
出版者： Weinheim: Blackwell Publishing Ltd
出版日期： 2015-10
出處： Cellular polymers, 2015-10, Vol.216 (20), p.2020-2031
資源來源： Wiley Online Library - AutoHoldings Journals
版權： 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
版權： COPYRIGHT 2016 Sage Publications Ltd. (UK)
版權： Copyright 2015 by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
識別號： ISSN: 1022-1352
識別號： ISSN: 0262-4893
識別號： EISSN: 1521-3935
識別號： DOI: 10.1002/macp.201500206 |
