Self-Healing Multiphase Polymers via Dynamic Metal–Ligand Interactions

Abstract

A new self-healing multiphase polymer is developed in which a pervasive network of dynamic metal-ligand (zinc-imidazole) interactions are programmed in the soft matrix of a hard/soft two-phase brush copolymer system. The mechanical and dynamic properties of the materials can be tuned by varying a number of molecular parameters (e.g., backbone/brush degree of polymerization and brush density) as well as the ligand/metal ratio. Following mechanical damage, these thermoplastic elastomers show excellent self-healing ability under ambient conditions without any intervention.

Dynamic ionic crosslinks enable high strength and ultrastretchability in a single elastomer

“…Recently, supramolecular elastomers comprising low glass transition temperature (T g ) polymer chains and weak dynamic bonds, such as hydrogen bonds 7 , metal-ligand coordination [8][9][10] , and ionic bonds [11][12][13][14][15] , have been designed for autonomic self-healing at room temperature. In contrast to most self-healing materials, these supramolecular elastomers do not require the input of any external energy (such as heat or light) [16][17][18][19][20] , healing agents (such as monomers and catalysts) 21,22 , plasticizers 23 , or solvents [24][25][26][27] .…”

Intrinsic Self-Healing Polymers Based on Supramolecular Interactions: State of the Art and Future Directions

“…In recent years, two strategies have been investigated in order to overcome this problem: The first method is to utilize a double network structure with incorporation of covalent crosslinks, which enhance the mechanical properties [56]. Another possibility is a multiphase design in which both hard and soft segments are utilized to feature both high mechanical properties and self-healing behavior at room temperature [55,194,262].…”

“…Guan and coworkers designed a multiphase network consisting of zinc-imidazole interactions in a hard/soft brush copolymer structure [194]. First, they copolymerized styrene and 4-vinylbenzyl chloride (5 and 10%) via free radical polymerization (approximately 140 repeating units).…”

Supramolecular thermoplastics and thermoplastic elastomer materials with self-healing ability based on oligomeric charged triblock copolymers

“…The crosslinks can for example be formed by multiple hydrogen bonds, [4][5][6][7][8][9][10][11][12][13][14][15] π-π stacking interactions, 16,17 ionic interaction [18][19][20][21] or metal-ligand interaction. [22][23][24][25] Supramolecular materials based on self-assembly of oligopeptides 26 and nucleobases 27 have also been reported. Even relatively weak hydrogen bonds in combination with phase segregation can form a rather strong network from low-molecular-weight components.…”