Grady Martha E, Beiermann Brett A, Moore Jeffrey S, Sottos Nancy R
Department of Mechanical Science and Engineering University of Illinois at Urbana-Champaign 1206 W. Green Street, Urbana, Illinois 61801, United States.
ACS Appl Mater Interfaces. 2014 Apr 23;6(8):5350-5. doi: 10.1021/am406028q. Epub 2014 Apr 1.
Thin films of mechanochemically active polymer were subjected to laser-generated, high amplitude acoustic pulses. Stress wave propagation through the film produced large amplitude stresses (>100 MPa) in short time frames (10-20 ns), leading to very high strain rates (ca. 1 × 10(7) to 1 × 10(8) s(-1)). The polymer system, spiropyran (SP)-linked polystyrene (PS), undergoes a force-induced chemical reaction causing fluorescence and color change. Activation of SP was evident via a fluorescence signal in thin films subject to high strain-rates. In contrast, quasi-static loading of bulk SP-linked PS samples failed to result in SP activation. Mechanoresponsive coatings have potential to indicate deformation under shockwave loading conditions.
对具有机械化学活性的聚合物薄膜施加激光产生的高振幅声脉冲。应力波在薄膜中传播，在短时间框架（10 - 20纳秒）内产生大振幅应力（>100兆帕），导致非常高的应变率（约1×10⁷至1×10⁸秒⁻¹）。聚合物体系，即螺吡喃（SP）连接的聚苯乙烯（PS），会发生力致化学反应，导致荧光和颜色变化。通过在高应变率下的薄膜中的荧光信号可以明显看出SP的活化。相比之下，对块状SP连接的PS样品进行准静态加载未能导致SP活化。机械响应涂层有潜力在冲击波加载条件下指示变形情况。
