Self‐Healing, Photothermal‐Responsive, and Shape Memory Polyurethanes for Enhanced Mechanical Properties of 3D/4D Printed Objects

Abstract

Additive manufacturing is a promising technology that can directly fabricate structures with complex internal geometries, which is barely achieved by traditional manufacturing. However, the mechanical properties of fused deposition modeling (FDM)‐printed objects are inferior to those of conventionally manufactured products. To improve the mechanical properties of the printed products, a series of novel thermoplastic polyurethanes with self‐healing properties, intrinsic photothermal effects, and excellent printability are designed and synthesized by introducing dynamic oxime–carbamate bonds and hydrogen bonds into the polymer chains. On‐demand introduction of near‐infrared (NIR) irradiation, direct heating, and sunlight irradiation enhances interfacial bonding strength and thus improve the mechanical properties of the printed product. Additionally, mechanical anisotropy of the printed products can be sophistically manipulated by regulating the self‐healing conditions. Support‐free printing and healing of damaged printed products are also achieved owing to the self‐healing properties of the material. Moreover, the as‐prepared materials exhibit shape‐memory properties NIR irradiation or direct heating effectively triggers shape‐memory recovery and demonstrates their potential in 4D printing by printing a man‐like robot. This study not only provides a facile strategy for obtaining high‐performance printed products but also broadens the potential applications of FDM technology in intelligent devices.

Flexible Photothermal Materials with Controllable Accurate Healing and Reversible Adhesive Abilities

“…Therefore, thanks to the comprehensive influences of these factors, XSBRZA/E composites exhibit amazing photothermal conversion efficiency beyond most of the photothermal materials, even at a tiny dose of the photothermal agent (Figure c and Table S3). ,,− ,, The excellent photothermal conversion properties of XSBRZA/E composites bring potential in photo-thermoelectric conversion, light-controlled self-healing, and the development of new photothermal applications.…”

“…5 Generally, obtaining considerable photothermal conversion capabilities requires the programming of chromophores into polymers or the addition of photothermal agents into the polymer matrix. Zeng et al 6 and Wang et al 7 separately programmed p-benzoquinone dioxime (BQDO, as a chromophore) into polyurethane networks for robust and nearinfrared (NIR) light-controlled healable elastomers. Although the elastomers exhibited excellent mechanical properties, the photothermal conversion efficiency was only ∼15%.…”

Personalized Medical Devices Connect Monitoring and Assistance: Emerging Wearable Soft Robotics

“…Compared with traditional material removal and cutting technology, additive manufacturing is a "bottom-up" manufacturing method for manufacturing solid parts through the gradual accumulation of materials. 41 In additive manufacturing technology, three-dimensional (3D) printing is a rapid prototyping technology that is based on digital model files and uses special 3D printing equipment to construct objects through layer-by-layer printing using powder or fusible metal or plastic and other adhesive materials. 3D printing technology is one of the main technologies for manufacturing soft robotics and is widely used in the manufacturing of soft robotics.…”

Recent Advances in the Additive Manufacturing of Stimuli‐Responsive Soft Polymers

“…[430] Self-healing technology has been growing continuously and develops new polymers and their composites, and smart materials with self-healing features. [431] Additionally, it is difficult for stimuli-responsive materials to withstand fractures or scratches during their service time. [432] Furthermore, responsive materials are more prone to fatigue and form cracks during the shape-morphing process.…”