Stretchable Self‐Healing Plastic Polyurethane with Super‐High Modulus by Local Phase‐Lock Strategy

Abstract

In this work, a multiblock polyurethane (PU‐Im) consisting of polyether and polyurethane segments with imidazole dangling groups is demonstrated, which can further coordinate with Ni2+. By controlling the ligand content and metal–ligand stoichiometry ratio, PU‐Im‐Ni complex with vastly different mechanical behavior can be obtained. The elastomer PU‐2Im‐Ni has extraordinary mechanical strength (61MPa) and excellent toughness (420 MJ m−3), but the plastic PU‐4Im‐Ni exhibits super‐high modulus (515 MPa), strength (63 MPa), and good stretchability (≈800%). The metal–ligand interaction between polyurethane segments and Ni2+ is proved by Raman spectra, dynamic mechanical analysis (DMA), and transmission electron microscopy (TEM). The polyurethane segments domain formed by microphase separation is dynamically “locked” by Ni2+ coordinated with imidazole, revealing a local phase‐lock effect. The phase‐locking hard domains reinforce the PU‐Im‐Ni complex and maintain stimuli‐responsive self‐healing ability, while the free polyether segments provide stretchability. Primarily, the water environment with plasticization effect serves as an effective and eco‐friendly self‐healing approach for PU‐Im‐Ni plastic. With the excellent mechanical performance, thermal/aquatic self‐healing ability, and unique damping properties, the PU‐Im‐Ni complexes show potential applications in self‐healing engineering plastic and cushion protection fields.

A Strategy of Thiolactone Chemistry to Construct Strong and Tough Self-Healing Supramolecular Polyurethane Elastomers via Hierarchical Hydrogen Bonds and Coordination Bonds

“…Remarkably, there is an incongruous contradiction between mechanical performance and healing capacity . Increasing the strength or density of the reversible interactions is beneficial to enhance the tensile strength, while the toughness and dynamics of the system are dramatically compromised and vice versa. , …”

“…39 Increasing the strength or density of the reversible interactions is beneficial to enhance the tensile strength, while the toughness and dynamics of the system are dramatically compromised and vice versa. 40,41 To address the aforementioned issues, a series of strategies have been proposed in recent years, among which phase regulation and sacrificial bonds are widely accepted and successfully demonstrated. 42−47 Guan et al designed a novel brush polymer that reversibly self-assembled into the microphase-separated nanostructure relying on hydrogen bonds.…”

Tannic Acid Crosslinked Self‐Healing and Reprocessable Silicone Elastomers with Improved Antibacterial and Flame Retardant Properties

“…[35] Importantly, no peak was observed at 2260 cm −1 , indicating that -NCO had completely reacted. [36][37][38] Figure 2b shows the glass transition temperature of the polymer, which also proved the successful synthesis of the product. The glass transition temperature (T g ) increases slightly from −113 to −111 °C with increasing TA fraction additionally, this was due to increased hydrogen bonding which hindered the mobility of the elastomer, but the elasticity still maintained a low glass transition temperature which facilitated self-healing.…”

Toughening Ionic Polymer Using Bulky Alkylammonium Counterions and Comb Architecture

“…Among them, ionic interactions differentiate from other dissociative interactions in that the bulk properties of polymers are governed by the dynamics of the ionic network . These dynamics are dependent on a variety of parameters including the quantity, nature, strength, and distance of ionic motifs as well as the chemical structure of the polymer backbone. − Notably, ionic soft polymers with low glass transition temperatures ( T g ) allow for active ion dynamics, resulting in extraordinarily tough soft materials. , However, due to the limited mobility of polymers in rigid polymer networks with a high T g , it is difficult to develop a universal strategy for toughening using ionic interactions without a decrease in elastic modulus.…”

“… 9 − 11 Notably, ionic soft polymers with low glass transition temperatures ( T g ) allow for active ion dynamics, resulting in extraordinarily tough soft materials. 12 , 13 However, due to the limited mobility of polymers in rigid polymer networks with a high T g , it is difficult to develop a universal strategy for toughening using ionic interactions without a decrease in elastic modulus.…”