Sustainable Reversible Patterning via Humidity-Switchable Self-Assembled Multilayers Induced by Photolithography.

Lithography plays a crucial role in the fabrication of intricate patterns. Materials that possess both lithographic capabilities and stimuli-responsive characteristics enable the realization of dynamic and controllable information processing. In this work, a self-assembled material with lithographic characteristics was obtained by using a photoresist as the photo-responsive layer and polyethyleneimine (PEI) as the additional layer. Interestingly, the synthesized photoresist based on 2-nitro-benzyl methacrylate undergoes a structural transition to form a polyacrylic acid (PAA) structure. Consequently, after lithography, the PEI/PAA structure could be selectively formed in the exposed areas. The structures in the exposed and non-exposed areas exhibit different humidity-responsive behaviors; thus, dynamic and controllable processing of lithographic information can be achieved. Unlike other stimuli-responsive processes under strong acid/base or ultraviolet light environments, these humidity-responsive processes have the advantages of mild conditions and environmental friendliness. This dynamic and controllable process based on the interaction with H2O is non-destructive and can achieve long-term cycling. Moreover, the nitrobenzyl-based photoresist exhibited excellent responsivity to 254 nm and electron-beam lithography (EBL), ultimately achieving a highest resolution of 40 nm. The structural changes occurring during the lithography process were investigated using ultraviolet-visible (UV-vis) spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The integration of lithography technique and responsive materials provides a novel approach for achieving dynamic and controllable information manipulation, with significant potential for diverse applications.