Cortical-Folding-Inspired Multifunctional Reduced Graphene Oxide Microarchitecture Arrays on Curved Substrates

Although controlled wrinkling is demonstrated to be a powerful tool for micro/nanofabrication, large-area fabrication of microarchitecture arrays on curved substrates by surface wrinkling still remains challenging. Inspired by the cortical folding, a facile method for transforming graphene oxide (GO) patterns into multiscale microarchitecture arrays on curved substrates is developed. Mass production of hierarchical GO papillae arrays can be realized by homogeneous compression of patterned GO/rubber bilayers. The reduced GO (rGO) papillae arrays show superhydrophobicity with tunable adhesion to water, enabling good performance in microdroplet manipulation. Besides, the papillae are capable of regulating the formation of microcracks in the rGO films upon stretching. Similar to the mechanical sensing system of spiders, a crack-based strain sensor with high gauge factor (approximate to 81), good linearity (0-15%), and fast responding speed (<40 ms) is demonstrated. In addition, the strain sensor is capable of detecting and recognizing multiple deformation modes including stretching, poking, and touching. This work reveals novel cortical folding morphology and provides a simple fabrication method for multifunctional hierarchical microarchitectures on curved substrates, which may find applications in biomimetic microstructures, smart wetting surfaces, and wearable electronics.

Automated summary

This study presents a simple method for manufacturing multiscale microarchitecture arrays on curved substrates by compressing patterned GO/rubber bilayers. The resulting structures exhibit superhydrophobic properties and the ability to regulate microcrack formation, serving as high-performance microdroplet manipulation devices and strain sensors.