Colloidal Crack Sintering Lithography for Light‐Induced Patterning of Particle Assemblies

Photoinduced patterning can generate intricate topographic structures, but it relies heavily on specialized materials, which limits its general usability. Here, colloidal crack sintering lithography (CCSL) is introduced, a patterning method based simply on a commodity polymer and water that interact with focused near-infrared light. Photothermal heating causes nanoscale sintering in polymer colloidal assemblies, which in turn induces controlled formation of cracks on the micron scale. Because light provides spatiotemporal control, individual cracks can be guided along precisely defined trajectories. Furthermore, this photo-driven sintering mechanism can be applied to subsequently convert such cracks into an open channel morphology. The result is reminiscent of positive resists in photolithographic patterning, as the precursor material is selectively removed along the irradiated path. Consequently, CCSL provides analogous functionality to photolithography in templating techniques such as shadow masks in physical vapor deposition and templated colloidal self-assembly.