Abstract:
Integrating 1D nanomaterials into 3D arrays or hierarchical structures is crucial to unlocking their complete potential in functional applications. This work highlights the significant influence of pH variations on the morphological evolution of three-dimensional zinc oxide foams (ZOFs) at relatively low temperatures, leading to the formation of diverse structures with varying aspect ratios and dimensions. Our findings underscore the role of alkaline conditions in fostering the evolution of dandelion-like 1D nanostructures, attributed to the intricate interplays of reaction kinetics and Ostwald ripening processes. Furthermore, the ZOF demonstrates potential applications in self-cleaning, oil/water separation, and human motion sensing. The ZOF is optimized to exhibit superhydrophobicity (water contact angle = 153 +/- 2 degrees) showcasing self-cleaning ability and enhanced oil-water separation performance following surface functionalization. The ZOF exhibits exceptional oil adsorption capacity (10-55 g/g) and superior stability, making it suitable for oil-water separation. Furthermore, our investigations showcase the biocompatibility and practical applicability in oil-water separation, both on surface and underwater, highlighting its efficacy in environmental remediation scenarios. Transitioning to wearable sensing, ZOF exhibits outstanding mechanical (compression strength increases by more than 130%) and piezoresistive characteristics (gauge factor = 1.036), precisely capturing a broad spectrum of human movements and tactile stimuli with rapid response times (similar to 60 ms). Furthermore, ZOF exhibits stability over 10,000 continuous tapping cycles, indicating the material's ability to maintain its piezoresistive properties over extended use. Overall, the multifaceted functionalities and versatility of the ZOF make it a promising material for environmental remediation, sensor technology, and human-machine interfaces.