Identifying Internal Stresses during Mechanophore Activation
Identifying Internal Stresses during Mechanophore Activation
复制标题
识别机械基团激活过程中的内应力
DOI：
10.1002/adem.202101080
复制
发表时间：
2021
影响因子：
3.6
通讯作者：
Davis, Chelsea S.
中科院分区：
文献类型：
--
作者：
Rencheck, Mitchell L.;Mackey, Brandon T.;Hu, Yu-Yang;Chang, Chia-Chih;Sangid, Michael D.;Davis, Chelsea S.
机械载体(MPS)在机械刺激下发生化学反应而变成荧光，机械刺激反映了施加的应力的大小和分布。MPS是一种新兴技术，用于航空、能源和汽车行业中聚合物材料的自我报告损伤传感应用。然而，MP对局部压力的反应的定量校准仍然是一个突出的挑战。本文提出了一种用局部流体静应力(σh)标定MP荧光激活强度(I)的方法。将单轴拉伸应用于由刚性球体(二氧化硅)嵌入MP功能化弹性体基质(螺吡喃(SPN)功能化聚二甲基硅氧烷(PDMS))组成的简单复合材料。通过共焦显微镜监测准静态变形时的荧光强度，获得了MP激活随外加单轴应变变化的原位观察结果。为了计算相关的应力场，采用了带粘结带单元的有限元分析。通过将有限元计算的σh与pDMS/SPN系统的I进行比较，直接确定了I与σ之间的线性关系。该方法可用于多种含MP材料体系的σh校正。
Mechanophores (MPs) undergo chemical reactions to become fluorescent in response to a mechanical stimulus that reflects the magnitude and distribution of applied stress. MPs are an emerging technology for self‐reporting damage sensing applications in polymeric materials in the aeronautical, energy generation, and automotive industries. However, quantitative calibration of the MP response to local stresses remains an outstanding challenge. Herein, a method to calibrate the intensity of the MP fluorescent activation (I) with local hydrostatic stresses (σh) is presented. Uniaxial tension is applied to a simple composite comprised of a rigid sphere (silica) embedded in a MP‐functionalized elastomeric matrix (spiropyran (SPN) functionalized polydimethylsiloxane (PDMS)). By monitoring the fluorescence intensity with a confocal microscope while a quasi‐static deformation is applied, in situ observations of MP activation as a function of applied uniaxial strain are obtained. To calculate the associated stress fields, a finite element analysis (FEA) with cohesive zone elements is employed. By comparingσh, calculated through FEA with theIof the PDMS/SPN system, a linear relationship betweenIandσhis directly determined. The technique presented can be employed for many MP‐containing materials systems to calibrateItoσh.