Biological tissues can grow stronger after damage and self-healing. However, artificial self-healing materials usually show decreased mechanical properties after repairing. Here, we develop a self-healing strengthening elastomers (SSEs) by engineering...
Loose connective tissue that widely exists in the human
body is
very tough and healable, due to the unique network formed by hyperbranched
and linear fibers. Inspired by such structure, we develop a class
of tough and healable polymeric glasses (THGs) by tailoring amine-carboxylate
salt bridges between a hyperbranched polymer and high-molecular-weight
linear copolymers. The high density of salt bridges leads to high
yield strength (up to 49.7 MPa) and Young’s modulus (1.1 GPa)
of THGs. Meanwhile, the large free volume of the hyperbranched polymer
and the molecular entanglements of the linear copolymers enable outstanding
toughness (up to 91.9 MJ/m3), outperforming most commercial
glassy polymers. More interestingly, THGs can be readily healed below
and around the glass-transition temperature after mechanical damage.
Therefore, this biomimetic approach enables the development of glassy
polymers with combination of high strength, excellent toughness, and
self-healing ability.
Suppressing vibrations and noises is essential for our automated society. Here, inspired by the hierarchical dynamic bonds and phase separation of mussel byssal threads, we synthesize high-damping supramolecular elastomers (HDEs) via simple onepot radical polymerization of butyl acrylate (BA), acrylic acid (AA), and vinylimidazole (VI). Interestingly, AA and VI not only form hydrogen bonds and ionic bonds simultaneously but also segregate into aggregates of different sizes, thereby successfully mimicking the hierarchical structure of mussel byssal threads. When applying external forces, the weak hydrogen bonds are broken at first and then the ionic bonds and aggregates are disrupted progressively from small to large deformations. Such multiple energy-dissipation mechanisms lead to the outstanding damping property of the HDEs. Therefore, the HDEs outperform commercially available rubbers in terms of sound absorption and vibration damping. Furthermore, the multiple energy-dissipation mechanisms impart the HDEs with high toughness (41.1 MJ/m 3 ), tensile strength (21.3 MPa), and self-healing ability.
Metallosupramolecular elastomers have attracted much
attention
due to their excellent mechanical properties, flexible tailoring of
performance, and responsiveness to photo and thermal stimuli. The
physicomechanical properties of metallosupramolecular elastomers are
highly dependent on metal salts and ligand units; however, the role
of counterions lacks practical exploration. To this end, we synthesized
a simple acrylate copolymer model and introduced copper salts with
different counterions to construct dynamic copper–nitrogen
coordination cross-linked networks. This approach generated a series
of elastomers with a tensile strength of over 10 MPa and a laser self-healing
efficiency of over 90% within 2 min. In particular, we studied the
effects of counterions on the thermodynamic, viscoelastic, mechanical,
photothermal, and self-healing properties of the materials. Therefore,
this work can provide instruction for the preparation and performance
tailoring of metallosupramolecular elastomers.
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