Facile Fabrication of Superomniphobic Polymer Hierarchical Structures for Directional Droplet Movement

We report a facile method for fabricating polymer hierarchical structures, which are the engineered, ratchet-like microscale structures with nanoscale dimples, for the directional movement of droplets. The fabricated polymer hierarchical structures with no surface modifier show hydrophobic, superhydrophobic, or omniphobic characteristics depending on their intrinsic polymer properties. Further treatment with a surface modifier endows the polymer surfaces with superomniphobicity. The fabricated polymer substrates with no surface modifier enable the movement of the water droplet along the designed track at almost no inclination of the substrate

Three-Dimensional Hetero-Integration of Faceted GaN on Si Pillars for Efficient Light Energy Conversion Devices

An important pathway for cost-effective light energy conversion devices, such as solar cells and light emitting diodes, is to integrate III–V (<i>e</i>.<i>g</i>., GaN) materials on Si substrates. Such integration first necessitates growth of high crystalline III–V materials on Si, which has been the focus of many studies. However, the integration also requires that the final III–V/Si structure has a high light energy conversion efficiency. To accomplish these twin goals, we use single-crystalline microsized Si pillars as a seed layer to first grow faceted Si structures, which are then used for the heteroepitaxial growth of faceted GaN films. These faceted GaN films on Si have high crystallinity, and their threading dislocation density is similar to that of GaN grown on sapphire. In addition, the final faceted GaN/Si structure has great light absorption and extraction characteristics, leading to improved performance for GaN-on-Si light energy conversion devices

Rapid custom prototyping of soft poroelastic biosensor for simultaneous epicardial recording and imaging

Printed biosensors are important for health monitoring and research purposes. Here, the authors report on the development of a soft poroelastic silicone based sensor which can be easily printed and is resistant to mechanical strain hysteresis, allowing for more accurate electrophysiology readings and imaging