Crazing in Glassy Block Copolymer Thin Films
Crazing in Glassy Block Copolymer Thin Films
复制标题
玻璃态嵌段共聚物薄膜中的裂纹
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
A. Crosby
中科院分区：
文献类型：
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作者：
Jong;A. Crosby
我们研究了对称聚苯乙烯-b-聚(2-乙烯基吡啶)(PS-b-P2VP)玻璃薄膜的银纹形成过程(银纹的形成、生长和破坏)。PS-b-P2VP是本研究的模型材料，因为它能够自组装成排列良好的片状微区，并且每个块具有相似的力学性能(玻璃化转变温度、银纹应力、纠缠相对分子质量和弹性模量)。这些属性使我们能够专注于两个主要的影响： ，有序微结构的影响和表面阶梯对玻璃聚合物薄膜银纹过程的影响。我们发现，与聚苯乙烯均聚物相比，有序的片层结构导致了微细化过程中银纹深度与薄膜厚度的比值较高，银纹增长速率较低。此外，与聚苯乙烯和PS-b-P2VP薄膜相比，表面阶梯或表面形貌中的纳米级台阶阻止了银纹的萌生，并显著降低了失效应变。
We investigate the crazing process (craze initiation, growth, and failure) in symmetric polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) glassy thin films. PS-b-P2VP is a model material for this study due to its ability to self-assemble into well-aligned lamellar microdomains and the similar mechanical properties for each block (glass transition temperature, crazing stress, entanglement molecular weight, and elastic modulus). These attributes allow us to focus on two primary effects: the effect of an ordered microstructure and the effect of surface terraces on the crazing process in thin glassy polymer films. We find that an ordered lamellar microstructure leads to a higher ratio of craze depth to film thickness in the micronecking process and a lower craze growth rate compared with polystyrene homopolymer. Additionally, surface terracing, or nanoscale steps in the surface topography, impedes craze initiation and significantly decreases the failure strain compared with polystyrene and PS-b-P2VP thin films...