Data from: Holographic sol-gel monoliths: optical properties and application for humidity sensing

Sol–gel monoliths based on SiO2, TiO2 and ZrO2 with holographic colourful diffraction on their surfaces were obtained via a sol–gel synthesis and soft lithography combined method. The production was carried out without any additional equipment at near room temperature and atmospheric pressure. The accurately replicated wavy structure with nanoscale size of material particles yields holographic effect and its visibility strongly depends on refractive index (RI) of materials. Addition of multi-walled carbon nanotubes (MWCNTs) in systems increases their RI and lends absorbing properties due to extremely high light absorption constant. Further prospective and intriguing applications based on the most successful samples, MWCNTs-doped titania, were investigated as reversible optical humidity sensor. Owing to such property as reversible resuspension of TiO2 nanoparticles while interacting with water, it was proved that holographic xerogels can repeatedly act as humidity sensors. Materials which can be applied as humidity sensors in dependence on holographic response were discovered for the first time.通过溶胶-凝胶合成与软光刻（soft lithography）联用的方法，成功制备了表面呈现全息彩色衍射效果的二氧化硅（SiO₂）、二氧化钛（TiO₂）及氧化锆（ZrO₂）基溶胶-凝胶整体材料（sol–gel monoliths）。该制备流程无需额外专用设备，可在近室温及常压环境下完成。经精准复刻的纳米级波纹颗粒结构可产生全息衍射效应，其可视性强弱与材料的折射率（RI）紧密相关。在体系中引入多壁碳纳米管（MWCNTs）可提升材料的折射率，同时凭借其极高的光吸收常数赋予材料吸光性能。针对性能最优的多壁碳纳米管掺杂二氧化钛样品，本研究进一步探索了其作为可逆光学湿度传感器的应用前景与潜在价值。得益于二氧化钛（TiO₂）纳米颗粒与水接触时可发生可逆再分散的特性，实验证实全息干凝胶（holographic xerogels）可重复用作湿度传感材料。本研究首次发现了可基于全息响应实现湿度传感的新型功能材料。