A huge
challenge for developing self-healing materials is achieving
a good compromisation between mechanical properties and self-healing
efficiency. For this purpose, a facile route by introducing N-(hydroxymethyl)acrylamide (NMA) as a thermal-catalyzed
self-cross-linker as well as a self-healing material into a soft polymer
system for tuning the mechanical properties in an easy way, resulting
in elastic and self-healing properties through a covalent and dynamic
network simultaneously, represents an exciting avenue for the development
of self-healing materials. Specifically, we propose a simple strategy
to synthesize a self-cross-linkable poly{(n-butyl
acrylate)-co-[N-(hydroxymethyl)acrylamide]}
(PBA
x
-co-PNMA
y
) amphiphilic copolymer prepared by radical
polymerization method, where x and y are BA and NMA ratios, respectively, based on the monomer composition
in the obtained copolymer. The mechanical properties and self-healing
efficiency of the copolymer can be easily tuned by controlling the
monomer ratios and varying the self-cross-linking reaction conditions.
PBA0.8-co-PNMA0.2 in bulk solid
state possesses a stretchability of up to 191%, maximum stress of
571 kPa, and a self-healing efficiency of 90% in ambient conditions
without any interventions. Owing to the hydrophobic nature of PBA
in the copolymer system, self-healing can be triggered even underwater.
Furthermore, a microscale thin film bestowed with identical self-healing
and mechanical properties can be fabricated and the behavior of the
copolymer in thin-film form was inspected using a pseudofreestanding
tensile tester machine. This work provides insight into the future
design of materials with elastic, self-cross-linking, and self-healing
properties, which are adjustable depending on the desired applications.