Design Guidelines for Block Copolymer‐Templated In ₂ O ₃ Nanowires: Linking Morphology, Sintering, and Volatile Organic Compounds Sensing Performanc

We provide design guidelines for obtaining functional indium (III) oxide nanowire (NW) (In ₂ O ₃ NW) meshes for chemiresistive sensing via a practical, single‐step templating route that utilizes a precursor‐infused block copolymer (BCP) ink. This approach realizes a long‐sought promise of BCP‐templated functional nanostructures: reproducible patterning of active sensing materials with tunable morphology and high scalability potential. By varying BCP molecular weight, we systematically tune NW geometry and network connectivity, correlate morphology with baseline resistivity and chemiresistive metrics toward volatile organic compounds (VOCs), and identify an optimal BCP molecular weight that maximizes sensitivity. An optimized thermal annealing protocol sinters the sensory NW mesh, increasing its electrical conductivity by two orders of magnitude and stabilizing chemical and microstructural state, which yields durable, repeatable responses. Using the optimized morphology and annealing protocol, we evaluate sensing against six types of model VOC air pollutants, demonstrating robust high sensitivity. By correlating the performance with structural parameters, we establish quantitative guidelines linking BCP molecular weight, NW geometry, percolation, electrical resistivity, and VOC detection sensitivity. This method combines the nanoscale precision and tunability of BCP templating with the practicality of spin‐coating processes, establishing a reproducible process blueprint compatible with large‐area deposition techniques, pending future optimization of strict process control parameters.