Photoreversible Bond-Based Shape Memory Polyurethanes with Light-Induced Self-Healing, Recyclability, and 3D Fluorescence Encryption

Abstract

Developing a shape memory polyurethane with high mechanical properties, excellent self-healing has become a huge challenge for the development of smart materials. Herein, we report the design and fabrication of a shape memory polyurethane network terminated with coumarin units (HEOMC-PU) to address this conundrum. The synthesized HEOMC-PU exhibits exceptional mechanical performance with a breaking elongation of 746% and toughness of 55.5 MJ•m −3 . By utilizing the dynamically reversible behavior of coumarin units to repair the damaged network, the efficient self-healing performance (99.2%) of HEOMC-PU is obtained. In addition, the prepared network and light-induced dynamic reversibility endow the HEOMC-PU with both liquid-state remoldability and solid-state plasticity, respectively, enabling polyurethane to be recycled and processed multiple times. Furthermore, based on the fluorescence responsive characteristic of coumarin, HEOMC-PU with a fluorescent pattern can be deformed into specific threedimensional configurations by combining photolithography, self-healing, and the shape memory effect. Such a multilevel and multidimensional anti-counterfeiting platform with rewritable fluorescent patterns and reconfigurable shapes can open up a new encryption approach for future intelligent anti-counterfeiting.

Mechanochromic Self-Healing Materials with Good Stretchability, Shape Memory Behavior, Cyclability, and Reversibility Based on Multiple Hydrogen Bonds

“…The shape memory behavior of PE-PU polymers was qualitatively assessed by the U-bending method. 18 For example, the PE-PU film was dried at 50 °C for 24 h under a vacuum condition and cut into the size of 10 mm × 5 mm × 0.5 mm. Initially, the permanent shape of PE-PU film was bent to the angle of ε max at room temperature.…”

Recent Advances in Tailored Fabrication and Properties of Biobased Self-Healing Polyurethane

“…73 Figure 7 a demonstrates the self-healing mechanism of coumarin derivatives introduced into the chain ends of polyurethane and occurring under UV irradiation. 74 Moreover, the hydroxyl group in coumarin allows it to be used as a chain extender to introduce self-healing properties into PU. To this end, Wong et al 71 incorporated 6,7-dihydroxy coumarin as chain extenders directly into the PU molecular chain and used the dimerization reaction of coumarin to confer self-healing ability to palm oil-based PU.…”

Photochromic Polyurethane Coatings with Cross‐Linked Structure and Self‐Healing Behavior Based on the FRET Effect

“…[19][20][21] Moreover, polyurethane is a kind of materials easy to be synthesized with adjustable structures, and fluorescent groups can be directly introduced into the backbone of polyurethane via the chain expansion process, which is expected to expand functional anti-counterfeiting materials based on the original industrial applications and provide photochromic properties. [22][23][24][25] Besides, polyurethane material contains hydrogen bonds within the polymer, resulting in good adhesion to most materials such as metal and glass, which is beneficial for used as coating.…”