Near‐Infrared Light/Thermal Dual‐Responsive Epoxy‐Based Polydiacetylene Composite for 3D Printing

Abstract

Polydiacetylene (PDA) is a promising material due to the chromatic transition through external stimulus. However, near‐infrared (NIR) light is on the periphery of attention to achieve the colorimetric change. Herein, an epoxy‐based PDA composite is prepared through a dual‐wavelength orthogonal photopolymerization strategy where 405 nm light and UV light are utilized in turn. The appearance of blue phase indicates that ene–yne‐conjugated PDA backbone is successfully formed in the composite. The generated PDA composite exhibits a blue‐to‐red color change upon heating. More interestingly, the fast chromatic transition is also observed under a laser diode at 1064 nm irradiation in the presence of a NIR dye (IR 1064). And such NIR light responsiveness of the composite upon NIR light irradiation is demonstrated by thermal imaging camera. Finally, the 3D printing technique is applied to the composite and the fabricated 3D pattern exhibits dual colorimetric transition in response to both heat and NIR light stimuli. Therefore, the newly proposed approach finds great applications in functional materials due to the unique dual thermal or NIR light stimuli responsiveness.

Fabrication of a Novel Fluorescein Embedded Photocomposite Based on Interpenetrating Polymer Network (IPN) and Its Application in 4D Printing

“…Under proper light irradiation, PEGDA and EPOX can be cured through free radical photopolymerization and cationic photopolymerization, respectively. [21][22][23][24] It is worth noting that the photo-curing of acrylate and epoxy resins in the composite can be viewed as orthogonal, chemoselective polymerization procedures since their polymerization mechanisms are intrinsically different. [17,[25][26][27] Here, a near UV/visible light source, LED@405 nm, was utilized to irradiate the formulation, and the polymerization kinetics of PEGDA and EPOX were continuously monitored by real-time Fourier transform infrared spectroscopy (RT-FTIR).…”

NIR-sensitized hybrid radical and cationic photopolymerization of several cyanines in combination with diaryliodonium bis(trifluoromethyl)sulfonyl imide

“…Here, the use of monomers with UV-filter function restricts their use for UV-initiated polymerization, while their excitation with NIR light was successful. 17 From this point of view, NIR systems have attracted remarkable interest, [18][19][20][21][22][23][24][25][26][27][28][29][30] particularly for uses in coatings and polymer synthesis. 17,31,32 NIR-sensitized photopolymerization was first developed in the printing industry.…”

“…From this point of view, NIR systems have attracted remarkable interest, 18–30 particularly for uses in coatings and polymer synthesis. 17,31,32 NIR-sensitized photopolymerization was first developed in the printing industry.…”

Achieving Rewritable Fluorescent Patterning on Dye-Doped Polymers Using Programmable Laser Direct Writing

“…As one of the most common lasers, carbon dioxide (CO 2 ) laser has been widely used in food, medicine, machinery and electronics, aerospace, and other fields with the characteristics of low-cost, simple operation, and high photothermal conversion efficiency. − The interaction between CO 2 laser and materials is mainly manifested as the thermal effect, which can be used in the surface treatment, cutting, patterning, and perforation of materials. − Recently, laser direct writing (LDW) as new technology has been widely used for the surface patterning of metals, ceramics, plastics, and other materials. LDW exhibits great potential in designing patterns, especially for polymers, in that the high-energy laser beam irradiates the materials to generate instantaneous high temperature, leaving permanent patterns on the polymers’ surface by carbonization, discoloration, vaporization, or foaming. − Typical applications are to make logos, images, texts, two-dimensional codes, or barcodes to ensure the identification and traceability of various commodities.…”