Zhang Xiaohua, Yager Kevin G, Douglas Jack F, Karim Alamgir
Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou 215006, China.
Soft Matter. 2014 May 28;10(20):3656-66. doi: 10.1039/c4sm00238e. Epub 2014 Mar 27.
We examine the effect of a moving in-plane temperature gradient on the ordering of cylinder-forming block-copolymers (BCP) in films containing immobilized nanoparticles that span the film thickness. In a previous paper, we reported the effect of static step oven-annealing of these films above the glass transition temperature Tg for a long period before ordering the BCP film at a much higher temperature. In the dynamic film annealing method of the present work, termed cold zone annealing (CZA), the material is continuously raised to a temperature somewhat above the glass transition temperature and then well above it, with a control of the heating time and thermal gradient. Oven annealing before ordering has been found to relieve residual stresses in the film associated with large thermal expansion of the film upon heating, eliminating the large scale target patterns induced by stresses effects associated with residual solvent and thermal expansion. By comparison, CZA naturally suppresses undesirable target patterning with enhanced ordering kinetics created through this thermal history.
我们研究了平面内移动的温度梯度对含有贯穿膜厚度的固定纳米颗粒的薄膜中形成圆柱状的嵌段共聚物（BCP）有序排列的影响。在之前的一篇论文中，我们报道了在比玻璃化转变温度Tg高得多的温度下对BCP薄膜进行有序排列之前，先将这些薄膜在玻璃化转变温度以上进行长时间静态阶梯炉退火的效果。在本工作的动态薄膜退火方法（称为冷区退火，CZA）中，材料被连续加热到略高于玻璃化转变温度，然后升温至远高于该温度，同时控制加热时间和热梯度。已发现有序排列前的炉退火可缓解薄膜中与加热时薄膜的大热膨胀相关的残余应力，消除由与残余溶剂和热膨胀相关的应力效应引起的大规模目标图案。相比之下，CZA通过这种热历史产生的增强的有序动力学自然地抑制了不期望的目标图案形成。
