Autonomic
crack-healing technology has become a common option for
reconstructing polymer networks against mechanical degradation, structure
mismatch, material fatigue, and even performance failure, but how
to precisely and easily trigger this healing process on the crack
interfaces is still a huge challenge. Here, we first found an autonomic
physicochemical crack-healing behavior featuring intrinsic controllability
and reversibility, based on nonionic poly(acrylamide-co-acrylonitrile) [P(AAm-co-AN)] with an upper critical
solution temperature (UCST). Under the fast synergistic action between
extrinsic deionized water and heat, the scratched P(AAm-co-AN) layer fully returned to the original flat form and was reworked
at least five times. Meanwhile, their corresponding optical and mechanical
performances also recovered almost 100%. In particular, the intrinsic
thermoresponsiveness of P(AAm-co-AN) takes a leading
role in this crack-healing process, in which both interchain transition
and topological entanglement come into play. It provides a facile,
rapid, precise, green, and autonomic crack-healing strategy for improving
polymer durability.
Embolization is often used to block blood supply for controlling the growth of fibroids and malignant tumors, but limited by embolic agents lacking spontaneous targeting and posttreatment removal. So we first adopted nonionic poly(acrylamideco-acrylonitrile) with an upper critical solution temperature (UCST) to build up self-localizing microcages by inverse emulsification. The results showed that these UCST-type microcages behaved with the appropriate phase-transition threshold value around 40 °C, and spontaneously underwent an expansion−fusion−fission cycle under the stimulus of mild temperature hyperthermia. Given the simultaneous local release of cargoes, this simple but smart microcage is expected to act as a multifunctional embolic agent for tumorous starving therapy, tumor chemotherapy, and imaging.
A “living” semi-rigid metal–organic–polymer framework (MOPF) was first built up with flexible UCST-type poly(acrylamide-co-acrylonitrile) and a rigid metal–organic framework by a one-pot method for reversible, controllable adsorption and confinement.
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