Rapid, On‐Command Debonding of Stimuli‐Responsive Cross‐Linked Adhesives by Continuous, Sequential Quinone Methide Elimination Reactions

Abstract

Adhesives that selectively debond from a surface by stimuli-induced head-to-tail continuous depolymerization of poly(benzyl ether) macro-cross-linkers within a poly(norbornene) matrix are described. Continuous head-to-tail depolymerization provides faster rates of response than can be achieved using a small-molecule cross-linker, as well as responses to lower stimulus concentrations. Shear-stress values for glass held together by the adhesive reach 0.51±0.10 MPa, whereas signal-induced depolymerization via quinone methide intermediates reduces the shear stress values to 0.05±0.02 MPa. Changing the length of the macro-cross-linkers alters the time required for debonding, and thus enables the programmed sequential release of specific layers in a glass composite material.

Poly(ethyl glyoxylate)-Poly(ethylene oxide) Nanoparticles: Stimuli-Responsive Drug Release via End-to-End Polyglyoxylate Depolymerization

“…[19][20][21] This provides the potential for signal amplification at low stimulus concentrations. End-caps responsive to stimuli such as light [22][23][24] , H 2 O 2 25,26 , thiols 24,27 , and mildly acidic conditions 28 have been reported and have been used in applications such as sensors 25,29,30 and responsive coatings or plastics [31][32][33] . The incorporation of a second polymer block has provided amphiphilic copolymers that self-assembled to form nanoparticles such as micelles and vesicles.…”

Fluoride degradable and thermally debondable polyurethane based adhesive

“…This was recently demonstrated by Phillips and co-workers who designed an adhesive that degrades on contact with fluoride ions. 42 In this system, fluoride ions caused degradation of an intractable, crosslinked material resulting in a dramatic weakening of the adhesive.…”

Chemical Design of Functional Polymer Structures for Biosensors: From Nanoscale to Macroscale

“…In particular, from the perspective of biosensing, many devices that can sensitively monitor biosignals (e.g., breath, pulse, sweat, and strain) have been successfully developed based on hydrogel materials. Furthermore, new designs for hydrogels (e.g., double-network hydrogels, dynamic bonding-assisted hydrogels, and nanocomposite-reinforced hydrogels) have been extensively investigated over the last decade, and new chemical reactions such as head-to-tail depolymerization [138,139,140] or self-propagating reactions [141,142] can be further integrated into hydrogels, giving rise to an autonomous response system. In the future, hydrogels could be used as a platform for theragnosis, a combination of diagnosis and therapeutics, which is an emerging concept in biomedicine.…”