Christie Dane, Register Richard A, Priestley Rodney D
Department of Chemical and Biological Engineering, Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544, United States.
ACS Cent Sci. 2018 Apr 25;4(4):504-511. doi: 10.1021/acscentsci.8b00043. Epub 2018 Feb 27.
Nanoscale compositional heterogeneity in block copolymers can impart synergistic property combinations, such as stiffness and toughness. However, until now, there has been no experimental method to locally probe the dynamics at a specific location within these structured materials. Here, this was achieved by incorporating pyrene-bearing monomers at specific locations along the polymer chain, allowing the labeled monomers' local environment to be interrogated via fluorescence. In lamellar-forming poly(butyl methacrylate--methyl methacrylate) diblock copolymers, a strong gradient in glass transition temperature, , of the higher- block, 42 K over 4 nm, was mapped with nanometer resolution. These measurements also revealed a strongly asymmetric influence of the domain interface on , with a much smaller dynamic gradient being observed for the lower- block.
嵌段共聚物中的纳米级组成不均匀性可赋予协同性能组合，如刚度和韧性。然而，到目前为止，还没有实验方法可以在这些结构化材料内的特定位置局部探测动力学。在此，通过在聚合物链上的特定位置引入含芘单体实现了这一点，从而可以通过荧光询问标记单体的局部环境。在形成层状的聚（甲基丙烯酸丁酯-甲基丙烯酸甲酯）二嵌段共聚物中，以纳米分辨率绘制了较高嵌段的玻璃化转变温度(T_g)在4纳米范围内有42K的强烈梯度。这些测量还揭示了域界面对(T_g)的强烈不对称影响，对于较低嵌段观察到的动态梯度要小得多。
