Single‐Step Photopolymerization of Tapered Micronozzle Arrays via Self‐Induced Lensing and Polymer Contraction

ABSTRACT Micronozzle arrays hold great promise for microfluidic and biomedical systems due to their ability to precisely and simultaneously control fluid emission across multiple channels. Here, we present a single‐step photopolymerization method for fabricating tapered micronozzle arrays by harnessing self‐induced microlensing and polymer contraction. Under vertical UV exposure through a photomask with donut‐shaped apertures, polymerization is spatially modulated by oxygen diffusion and UV attenuation caused by photoinitiators. Ring‐shaped polymer structures initially form and evolve into hollow cylinders with wall thinning, followed by broadening driven by refractive focusing and light divergence along the optical axis. At high initiator concentrations, polymer shrinkage induces inward contraction of the cone walls above the thinnest region, producing sharply tapered hollow cones. We demonstrate tunability of the tapering angle, nozzle height, wall thickness, and tip opening by adjusting photomask geometry, monomer layer thickness, and initiator concentration. The resulting structures are embedded in a thin, freestanding polymer film while preserving open base apertures. The film exhibits excellent mechanical integrity and enables reliable, parallel emulsion droplet generation when integrated into a simple fluidic setup. This scalable, alignment‐free approach offers a versatile platform for high‐density, 3D micronozzle arrays with programmable geometry, suited for advanced microfluidic and drug injection applications.