Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States.
ACS Nano. 2015 Apr 28;9(4):3896-906. doi: 10.1021/nn5071827. Epub 2015 Mar 17.
For the promise of self-assembly to be realized, processing techniques must be developed that simultaneously enable control of the nanoscale morphology, rapid assembly, and, ideally, the ability to pattern the nanostructure. Here, we demonstrate how photothermal gradients can be used to control the ordering of block copolymer thin films. Highly localized laser heating leads to intense thermal gradients, which induce a thermophoretic force on morphological defects. This increases the ordering kinetics by at least 3 orders of magnitude compared to conventional oven annealing. By simultaneously exploiting the thermal gradients to induce shear fields, we demonstrate uniaxial alignment of a block copolymer film in less than a second. Finally, we provide examples of how control of the incident light field can be used to generate prescribed configurations of block copolymer nanoscale patterns.
为了实现自组装的承诺，必须开发加工技术，这些技术必须同时能够控制纳米级形态、快速组装，并且理想情况下能够对纳米结构进行图案化。在这里，我们展示了如何利用光热梯度来控制嵌段共聚物薄膜的有序排列。高度局域化的激光加热会导致强烈的热梯度，从而在形态缺陷上产生热泳力。与传统的烤箱退火相比，这至少将有序动力学提高了 3 个数量级。通过同时利用热梯度来诱导剪切场，我们在不到一秒的时间内展示了嵌段共聚物薄膜的单轴取向。最后，我们提供了一些示例，说明如何控制入射光场来生成嵌段共聚物纳米图案的预定配置。
