Researchers unveil deep-foam photolithography for ultra-high-resolution biomimetic printing

Scientists have developed deep-foam photolithography, a spatially controlled foaming process that initiates polymer scission and cross-linking throughout a film using penetrating UV-A light. Subsequent hypotonically driven solvent permeation creates nucleated pores that expand and collapse, yielding foams with up to 20,000 dots per inch resolution and the ability to print white and greyscale without ink. The technique produces mechanically expanded structures with aspect ratios of 20 × and surfaces that exhibit lotus-like super-hydrophobicity.

Demonstrated on a range of polymer systems—including polycarbonate, PET, polysulfone and PMMA—the approach enables precise patterning of foamability, wettability, optical properties and thickness for applications such as high-resolution printing, microfluidic devices and picolitre liquid capture. The authors also show the method’s scalability to fibre mats and its compatibility with multiple photoinitiators. Funding was provided by JSPS, JST and Japan’s MEXT research programmes.