Recently, the research group led by Prof. Songshan Zeng from Macao Institute of Materials Science and Engineering, Faculty of Innovation Engineering, Macau University of Science and Technology, published important research results on innovative thermochromic materials in a leading international journal "Chemical Engineering Journal" (Impact factor:13.2; MUST is the sole affiliated institution of this research). This research pioneers a new paradigm for synergistic integration of stimuli-responsive photonic crystals with adaptive absorbers, enabling scalable fabrication of color-switchable devices with customized control capabilities and applications in dynamic anti-counterfeiting, smart labeling, disposable smart packaging labels, camouflage, and encryption.
This study overcomes the drawbacks of limited color transition in traditional thermochromic dyes by leveraging the synergistic mechanisms of “the dynamic helical pitch-regulated color spectra” and “incoherent scattering-controlled color saturation”. Specifically, the upper layer, based on semi-transparent hydroxypropyl cellulose (HPC) cholesteric liquid crystals (CLCs), exhibits impressive optical characteristics of concentration- and temperature-dependent reflective structural colors, covering the spectral region from ultraviolet (UV) to near-infrared (NIR) due to the precise modulation of helical pitch (p). The basal thermochromic powders (TCPs), strategically positioned beneath the HPC layer, exhibit color switching between white and black, and can serve as “dynamic light absorbers” to regulate the incoherent scattering and thus affect the saturation of structural colors. Therefore, a single integrated device composed of HPC CLCs and TCPs can display a smooth color transition, covering the full visible gamut, even including black and white under thermal stimuli. When combined with a conductive substrate, the hybrids enable electrothermal multicolor displays. More importantly, advanced optical applications in dynamic anti-counterfeiting, smart labeling, disposable smart packaging labels, camouflage, and encryption are realized by embedding patterned TCP arrays with different thermal response threshold temperatures beneath HPC CLCs.
Fig. 1 Design and application of the thermally responsive hybrids, composed of HPC CLCs and TCPs.
Fig. 2 Applications of integrated thermochromic devices in anti-counterfeiting, camouflage, and electrothermal multicolor displays.
Link to the article: https://doi.org/10.1016/j.cej.2025.166349
Title: Synergistic dynamic pitch and incoherent scattering enabling programmable cellulose thermochromic hybrids with UV-Vis-NIR broad modulation and multifunctionality
First author: Dr. Binhong Yu, M.S. student Ziyan Chen
Corresponding author: Dr. Binhong Yu, Prof. Songshan Zeng
This study was financially supported by the Science and Technology Development Fund (FDCT), Macao SAR (No. 0149/2022/A), and (No. 0046/2024/AFJ), and the Guangdong Science and Technology Department.
