光热转换效应驱动微管内表面起皱及其光操控微流体输运的应用

Surface instability-driving surface wrinkling has a wide potential in the applications such as surface patterning and flexible devices. So far, it is a great challenge to realize the surface wrinkling on a non-planar substrate with a negative curvature including the typical microtube internal surface for extending the unprecedented application fields. In the present project, stiff internal shell/soft microtube systems composed of photothermal effect-responsive components will be fabricated, when the soft microtube is used as the substrate. When exposed to light of an appropriate wavelength, the surface wrinkling on microtube internal surface will be reversibly induced owing to the photothermal effect of the introduced materials. Meanwhile, the temperature field and microtube deformation such as the internal radium will be triggered by the photothermal effect. Here the synergistic effect from the surface wrinkling on microtube internal surface, the microtube deformation and the temperature field will be exploited to drive the photo-manipulated microfluidic transport. Combined with the theoretical results and control experimental results, the underlying physics related to the photothermal-induced surface wrinkling on the microtube internal surface will be revealed. The current project will deepen our understanding the universal stress-relaxation problems in composite materials, as well as the mechanism of the formation of internal soft organs and the related lesion. More importantly, the combined effect from photothermal effect-induced surface wrinkling on microtube internal surface, the microtube deformation and the temperature field will provide a novel combined mechanism responsible to the photo-controlled microfluidic transport, which will direct the subsequent material design and optimization, and thus promote greatly the development and application of the photo-controlled microfluidic technology.

表面失稳驱动的表面起皱在表面图案化和柔性器件等领域有广阔的应用前景。如何实现负曲率基底如典型的微管内表面起皱，并拓展其相关领域的应用是目前面临的一项极具挑战性课题。本项目拟精心设计引入光热转换效应组分来可控构筑基于微管内表面形成的、多种组合类型的硬内壳/软外管系统；利用材料光热转换效应来同时可逆触发微管内表面起皱、微管形变和温度场的形成；进而探索该体系在光操控微流体输运等领域的应用。本项目通过系列对比实验，结合理论模拟计算，深入揭示负曲率基底的微管内表面起皱的物理机制，由此深化对复合体系普适性应力松弛问题的理解，并促进对动物体内管腔器官的内粘膜起皱与内粘膜相关病变的认识。更重要的是，本项目开发的光热效应同时可逆诱导的微管形变、温度场、微管内表面失稳形成的微结构拓扑图案的共同作用，有望作为一种新的光操控微流体运动的协同驱动机制，来指导其材料设计与优化，以期极大促进光控微流体技术的发展与应用。

作为一种新的表面微纳构造技术，表面失稳驱动的表面起皱显示了其独特的优势。如何利用不同曲率基底，特别是负曲率表面的表面起皱行为和起皱形貌特性来拓展其在微流控等相关领域的应用，仍是目前表面起皱研究面临的一项挑战。为此，本项目:1）开发了一种简单的连续挤出交联成纤技术，首次实现了超长聚二甲基硅氧烷（PDMS）微纤和微管的连续批量化制备，破解了PDMS微纤，特别是PDMS微管形貌可控与尺寸可调、连续化的制备难题，有望推动PDMS微纤/微管在先进织物器件、微流控芯片、人造血管和柔性电子器件等相关领域的应用。2）开发了一种简单高效的超声辅助溶胀沉积技术，一锅法实现了在不同曲率/形貌/种类弹性基底表面可控构筑具有光热效应和导电性能等功能的膜/壳层，以及对应的表面起皱的同时诱导。进而基于所得的起皱核壳结构PDMS复合功能微纤发展了一类高性能的超疏水柔性应变传感器，并应用于不同环境的声纹识别和人体运动检测等。基于液晶弹性体的热致收缩变形能力和其表面沉积的功能壳层的光热效应，发展了一类新型的光控纤维致动器，揭示了所涉及的纤维光驱变形与趋光运动新机制。3）利用PDMS微管与铺设-包埋技术的有机结合，实现了任意铺设路径、任意微流通道形貌的微流池芯片的可控构筑，为进一步的微量产物操纵和分类、微流体输运模拟等奠定基础；进而与起皱的PDMS复合功能纤维基柔性应变传感器集成，实现了微流通道内微流体的流速检测。4）利用PDMS微管内壁聚合沉积的光热效应功能壳层，实现了光诱导的微管负曲率内表面起皱。基于偶氮基元的多重光响应特性（如光热效应、光致顺反异构和光致取向等），首次构筑了偏振光响应的高灵敏的动态取向起皱体系，实现了任意皱纹取向的可控制备，并成功应用于光学可重构信息存储、防伪和信息加密/解密等方面。上述研究结果，极大深化了人们对不同曲率膜/基体系表面起皱机制的理解，为进一步实现表面起皱基高性能功能器件的构筑与先进应用打下坚实基础。现已发表SCI学术论文15篇（如Angew. Chem. Int. Ed., Adv. Funct. Mater., Chem. Eng. J., Carbon, ACS Appl. Mater. Interfaces），获1项授权专利和申请6项发明专利。