Adaptive fluid-infused porous films with tunable transparency and wettability

• Published in: Nature materials 2013-06, Vol.12 (6), p.529-534
• Main Authors: Yao, Xi, Hu, Yuhang, Grinthal, Alison, Wong, Tak-Sing, Mahadevan, L., Aizenberg, Joanna
• Format: Article
• Language: English
• Subjects: 639/301/119/544; 639/301/299/1013; Biomaterials; Condensed Matter Physics; Droplets; Environmental changes; Free surfaces; letter; Liquid flow; Materials elasticity; Materials Science; Nanocomposites; Nanomaterials; Nanostructure; Nanostructures - chemistry; Nanotechnology; Optical and Electronic Materials; Optics and Photonics; Pores; Porosity; Porous materials; Strategy; Substrates; Surface Properties; Tensile Strength; Topography; Transparency; Wettability
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/nmat3598

Designing synthetic surfaces whose properties dynamically adapt in response to mechanical stimuli is challenging. Now, liquid-infused nanoporous elastic substrates that respond to stretching by continuously changing their transparency and wettability—a consequence of smooth variations in surface roughening as the liquid flows inside the pores—are demonstrated. Materials that adapt dynamically to environmental changes are currently limited to two-state switching of single properties, and only a small number of strategies that may lead to materials with continuously adjustable characteristics have been reported 1 , 2 , 3 . Here we introduce adaptive surfaces made of a liquid film supported by a nanoporous elastic substrate. As the substrate deforms, the liquid flows within the pores, causing the smooth and defect-free surface to roughen through a continuous range of topographies. We show that a graded mechanical stimulus can be directly translated into finely tuned, dynamic adjustments of optical transparency and wettability. In particular, we demonstrate simultaneous control of the film’s transparency and its ability to continuously manipulate various low-surface-tension droplets from free-sliding to pinned. This strategy should make possible the rational design of tunable, multifunctional adaptive materials for a broad range of applications.