Fabricating a single polymer network with a combination of a multi-shape memory effect (multiple-SME), solid-state plasticity, recyclability and self-healing behavior remains a challenge. We designed imine bond and ionic hydrogen bond dual cross-linked polybutadiene (PB) networks. The resulting PB networks showed a triple-shape memory effect, where imine bonds could be used to fix the permanent shape and ionic hydrogen bonds and glass transition acted as the transition segments for fixing/releasing the temporary shapes. Additionally, the dual dynamic bonds offered PB networks outstanding solid-state plasticity, recyclability and self-healing behavior. This strategy provides some insights for preparing shape memory polymers integrating multiple-SME and multi-functionality.

Recyclable, Self-Healing, Thermadapt Triple-Shape Memory Polymers Based on Dual Dynamic Bonds.

Emulsion confinement self-assembly regulated lanthanide coordinating polymeric microparticles for multicolor fluorescent nanofibers

Stimuli-responsive structurally dynamic polymers are capable of mimicking the biological systems to adapt themselves to the surrounding environmental changes and subsequently exhibiting a wide range of responses ranging from self-healing to complex shape-morphing. Dynamic self-healing polymers (SHPs), shape-memory polymers (SMPs), and liquid crystal elastomers (LCEs), which are three representative examples of stimuli-responsive structurally dynamic polymers, have been attracting broad and growing interest in recent years because of their potential applications in the fields of electronic skin, sensors, soft robots, artificial muscles, and so on. Recent advances and challenges in the developments toward dynamic SHPs, SMPs, and LCEs are reviewed, focusing on the chemistry strategies and the dynamic reaction mechanisms that enhance the performances of the materials including self-healing, reprocessing, and reprogramming. The different dynamic chemistries and their mechanisms on the enhanced functions of the materials are compared and discussed, where three summary tables are presented: A library of dynamic bonds and the resulting characteristics of the materials. Finally, a critical outline of the unresolved issues and future perspectives on the emerging developments is provided. 

Progress in Utilizing Dynamic Bonds to Fabricate Structurally Adaptive Self‐Healing, Shape Memory, and Liquid Crystal Polymers

Shape memory polymers (SMPs) are, by far, one of the most intriguing subjects of smart materials with myriads of applications in various disciplines, such as biomedical, aerospace, automotive, and so on. By compiling the durable elasticity of elastomers and SMPs, one can obtain a low-weight material with exclusive recovery abilities and cost-effective features. However, elastomer-based SMPs have significant drawbacks in the case of mechanical and conductive properties, which are usually resolved by introducing nanofillers in the elastomer matrix. The resultant materials are known as polymer nanocomposites in which spectacular and amended properties could be observed. This purpose is accomplished by effectively disperse and distribute the fillers throughout the matrix and, indeed, by establishing a robust interaction between the polymer chains and filler components. Furthermore, adding functional fillers can enable the SMPs’ responsivity to other stimulation methods rather than heat, such as electricity, magnetic field, and light, expanding their applications where heat stimulation is unsatisfactory. This paper is dedicated to laying a solid foundation of shape memory effect in elastomeric polymers, procedures of composite fabrication, as well as addressing the amelioration of thermal, mechanical and electrical properties of SMP (nano-)composites.

Tracing evolutions of elastomeric composites in shape memory actuators: A comprehensive review

Synthesis and Properties of Multistimuli Responsive Shape Memory Polyurethane Bioinspired from α-Keratin Hair

Exploring multiple functions of diarylsemipinacol linked to the saturated ethylene-propylene elastomer: from the dynamic covalent networks to tailoring its macroscopic performance

Reversible stimuli-responsive luminescent polymers with adaptable mechanical properties based on europium-malonate complex

Covalent adaptable networks (CANs) have recently received extensive interests due to their reprocessability and repairability. Rethinking the libraries of the published CANs, most of them are fabricated by one/two-component reactions and few cases utilize multi-component reactions to construct CANs while multi-component reactions are conductive to tailoring the properties of polymers due to their structural designability and flexible choice of raw materials. A novel kind of dynamic covalent bond named aminoesterenamide is presented through three-component reaction between acetoacetyl, amine and isocyanate. Aminoesterenamide exhibits thermal reversibility through dissociating into vinylogous urethane and isocyanate. When it is used to prepare CANs, the synthesized polymer networks can be reprocessed many times via the exchange reaction between aminoesterenamides. Moreover, the forming of aminoesterenamide involving three starting components imparts CANs with great freedom to tailor their properties. Therefore, the authors believe this method that utilizes three-component reaction to fabricate CANs would bring new stories and perspectives to the exploration of new types of CANs.

Youwei Ma

Papers

Exploring multiple functions of diarylsemipinacol linked to the saturated ethylene-propylene elastomer: from the dynamic covalent networks to tailoring its macroscopic performance

Reversible stimuli-responsive luminescent polymers with adaptable mechanical properties based on europium-malonate complex

Aminoesterenamide Achieved by Three-Component Reaction Heading toward Tailoring Covalent Adaptable Network with Great Freedom.