Rice-leaf-mimetic cellulosic paper as a substrate for rewritable devices and biolubricant-infused “slippery” surfaces

Biomimetics has revolutionized materials innovation by drawing inspiration from biological systems. Cellulosic paper, a sustainable biomaterial, offers immense potential for biomimetic research. Paper-based biomimetic materials, which replicate the structures and functionalities of natural materials by utilizing the cellulosic fiber network as a substrate or skeleton, provide customizable functional properties, thereby enabling advanced applications. Here, we introduce rice-leaf-mimetic paper, inspired by the leaf's microstructure and biowax-based cuticle. This paper exhibited self-cleaning superhydrophobicity and showcased possibilities for additional functionalities, including antibacterial properties and food preservation. We herein propose its utilization as a substrate for rewritable and biolubricant-infused surfaces. These somehow distinct surfaces draw inspiration from the chemistry and microstructure of the rice leaf. Although incorporating hydrochromic dyes enables rewritability, controlling the retention time of colors remains challenging. The biowaxy structure of the paper prolongs color maintenance by inhibiting water evaporation. Moreover, the hierarchically rough microstructure of rice-leaf-mimetic paper effectively stores biolubricant molecules, reducing friction and enhancing slipperiness. Surface microcavity ratio analysis provides insights into the paper's lubricant-storability. The surface engineering of rice-leaf-mimetic paper using hydrochromic dyes or biolubricants holds potential for designing novel materials. Leveraging the mass-producibility of papermaking processes, in conjunction with the broad concepts of biomimetics and surface engineering, expands the possibilities for materials innovation.