In nature, communication often transcends the visible spectrum. While humans rely predominantly on visual and auditory signals, certain animals have evolved sophisticated mechanisms using infrared emission for survival and interaction. Ground squirrels, for instance, utilize spontaneous infrared thermal signaling by increasing blood flow to their tails, emitting deceptive heat patterns to deter predators like rattlesnakes. This biological strategy inspires a new class of smart materials capable of dual-mode temporal communication—simultaneously encoding information in both optical and thermal domains. Herein, we present a digitally programmable polymeric phase-change material that enables live evolution of both optical and infrared images over time, where time itself becomes the encoded variable.
The core of this system lies in a light-curable precursor composed of stearyl acrylate (a crystallizable monomer), 1,6-hexanediol diacrylate (a crosslinker), and Irgacure 819 (a photoinitiator). By preheating the mixture to 70 °C, the liquid state is achieved for uniform dispersion and curing. A commercial projector delivers spatially controlled digital light patterns, enabling pixelated polymer network formation with precise tuning of crosslink density. Regions exposed to longer light durations develop higher crosslinking densities, reducing the availability of unreacted monomer and altering crystallization kinetics. Conversely, shorter exposure results in lower crosslinking and greater molecular mobility, promoting later but more complete crystallization.
Upon cooling from the melt state, these differences manifest dynamically. Initially transparent at 70 °C, the film undergoes time-dependent changes: regions with higher crosslink density crystallize first, becoming opaque earlier, while less crosslinked zones remain clear longer. As equilibrium crystallization progresses, the contrast reverses—those initially slow-crystallizing regions achieve higher crystallinity and opacity. This leads to a visually evolving pattern; for example, a cup-shaped design transforms into a face-like shape over time, as demonstrated in real-time video capture. The process is fully reversible through reheating to the melt state, allowing repeated use.
This temporal evolution is not limited to simple shapes. We demonstrate complex, high-contrast optical patterns such as QR codes fabricated using PSA-8/24 combinations—where 8 s and 24 s curing times define the foreground and background, respectively. In the melt state, no information is readable. However, after cooling beyond 300 seconds, sufficient optical contrast emerges to enable scanning. Similarly, a layered QR code system reveals hidden temporal information only after a specific delay, enhancing security beyond conventional static QR systems.
Beyond optical modulation, the exothermic nature of crystallization enables infrared-based temporal communication. An optically invisible pattern becomes detectable under infrared imaging during controlled cooling, peaking at around 20 seconds post-cooling before fading due to thermal equilibration.Fibrillarin Antibody Description This allows for time-specific retrieval of encrypted data without external power sources.PCCA Antibody manufacturer Furthermore, even when obscured by complex optical backgrounds, patterns can be recovered as transient infrared signals upon heating and cooling cycles, mimicking natural thermoregulatory behaviors seen in animals.PMID:34788414
By integrating multiple curing times, we create multi-stage infrared displays—such as a night-blooming epiphyllum or a squirrel-snake interaction—where features emerge and vanish sequentially. These dynamic transitions replicate biological strategies of threat display and camouflage, demonstrating the material’s potential in secure, adaptive, and self-evolving communication platforms.
This work establishes a foundation for next-generation smart materials combining programmable phase transitions with spatiotemporal control. Its simplicity, reversibility, and dual-mode functionality open pathways for applications in anticounterfeiting, secure data storage, adaptive optics, thermal regulation, and responsive 3D/4D printing. Ultimately, by drawing inspiration from nature’s own communication tools, we unlock a new dimension of intelligent material behavior—one where time is not just a measure, but a message.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com
