A universal strategy for large-scale and controlled fabrication of conductive mesoporous polymer monolayers

A bottom-up approach for constructing large-area ultrathin nanolayers with meso-architectures and simultaneously patterning them on the required substrates is still facing a significant challenge thus far. In this work, polydopamine tightly adheres to substrate surfaces, then adsorbs and assembles amphipathic micelles to form a closely arranged monolayer. This surface modification enables the oriented growth of different precursors to prepare functional monolayer coating of various mesoporous materials with regular arrays and ultrathin thickness, including polymers (polypyrrole (PPy) and polyaniline (PANi), etc.) and metal oxides (tin oxide (SnO₂), etc.). Furthermore, this process allows for the direct integration of material construction and device fabrication in one step. The resultant single-layer mesoporous PPy-based gas sensor device achieves an excellent sensing response to ammonia (concentration as low as 200 ppb), with an extremely rapid response time (4 s) and recovery time (13 s). This work provides a general control on engineering mesoscale materials and effective integration of material growth, structural control, and device fabrication for potential applications.