Morphological features and dewetting behaviour of thin polymer films coated on porous substrates
Morphological features and dewetting behaviour of thin polymer films coated on porous substrates
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DOI：
10.1016/j.matpr.2021.01.929
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发表时间：
2021-03
期刊：
影响因子：
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通讯作者：
Rahul Sathyanath;Sreeram K. Kalpathy
中科院分区：
文献类型：
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作者：
Rahul Sathyanath;Sreeram K. Kalpathy
当加热到玻璃化转变温度以上时，涂在非润湿基板上的聚合物薄膜往往变得不稳定和潮湿。这种动力学与需要非连续和排列的聚合物薄膜的有机微电子和光刻等应用有关。在一些情况下，所关注的基材由于其多孔表面而具有有限的渗透性，如在纸、织物或砂岩中，这可能会改变液体膜的流体动力学。本文报道了聚苯乙烯薄膜脱湿不同孔径纳米孔氧化铝膜的模型实验。聚苯乙烯薄膜是通过自旋涂覆在甲苯基溶液中制备的，并加热到高于玻璃化转变温度以引发脱湿。研究了退火时间对薄膜形貌的影响。在退火过程中，薄膜使多孔衬底软化。然而，当孔隙变得饱和时，多余的聚合物自组织成均匀的涂层。通过数值模拟，从流体力学的角度解释了渗透基材附近液膜脱湿的动力学过程。
Polymer thin films coated onto non-wetting substrates tend to become unstable and dewet when heated above the glass transition temperatures. Such dynamics are relevant to applications like organic microelectronics and lithography that require non-continuous and arrayed thin polymer films. In several situations, the substrate of interest has finite permeability due to its porous surface, as in paper, fabric, or sandstones, which may modify the hydrodynamics of a liquid film. In the present work, we report model experiments of thin polystyrene films dewetting nanoporous alumina membranes of different pore sizes. Polystyrene films are prepared by spin coating a toluene-based solution, and heated above the glass transition temperature to initiate dewetting. The effect of annealing time on morphologies of the film is studied. During annealing, the film dewets the porous substrate. However, as pores become saturated, excess polymer self-organizes into a uniform coating. The dynamics of liquid film dewetting near permeable substrates are explained from a fluid mechanical perspective through numerical simulations.