Year: 2026
Type: preprint
Abstract: Polymer systems exhibiting structural color represent a promising class of materials for 3D printing due to their capability to adapt their properties in response to external stimuli. Hydroxypropyl cellulose (HPC) stands out for its ability to form cholesteric liquid crystalline phases that exhibit vivid structural colors. In this work, we introduce a digital light processing strategy to fabricate complex 3D structures with tunable, stimuli-responsive structural color using methacrylated HPC (HPC-MA). By formulating an aqueous ink system containing 58 to 70 wt% HPC-MA and establishing a pre-print equilibration protocol, cholesteric order is developed and covalently locked into the printed architecture via photopolymerization. The resulting 3D printed structures display bright, iridescent structural colors, tunable within the entire visible spectrum. The thermoresponsive properties of the printed structures are investigated both in a dried and a water-swollen state. Notably, the thermochromic behavior exhibits opposing trends in both environments with increasing temperature inducing a redshift in the dry state but a blueshift in the aqueous state. Finally, we demonstrate the practical utility of this approach in zero-power visual humidity sensing and biomimetic adaptive camouflage. The integration of structural color, stimuli-responsiveness, and 3D geometric freedom opens avenues towards next-generation 4D printing, adaptive materials, and autonomous sensing.
Source: ChemRxiv
Institution: Heidelberg University
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Funder: Deutsche Forschungsgemeinschaft
OpenAlex ID: W7221455566