Covalently Cross-Linked and Mechanochemiluminescent Polyolefins Capable of Self-Healing and Self-Reporting

Abstract

Compared with non-cross-linked and dynamically covalent polymers, covalently cross-linked networks are irreplaceable in many areas; however, they are difficult to repair once fractured, due to limited polymer chain diffusion after cross-linking. Herein, the authors have reported a new kind of permanently cross-linked polyolefin, which when attached with amide side groups, yield mechanically robust yet readily repairable materials. A key is to use low cross-linking density, which enables satisfactory elasticity and chain mobility for thermodynamically favored healing. Another key is to incorporate dense hydrogen bonds that can undergo reversible associations. These factors jointly promise polyolefin networks with good mechanical properties and self-healing performance (recovered spontaneously up to 96% of its original tensile strength). More importantly, by means of mechanochemiluminescence from 1,2-dioxetane, which serves as the cross-linker and built-in self-reporting stress probe, a microscopic evaluation of how the chain entanglement proceeds upon healing and how failure occurs in the network can be obtained.

Mechanochemiluminescent Hydrogels for Real-Time Visualization of Chemical Bond Scission

“…A general procedure to prepare the mechano-chemiluminescent swelling hydrogels was depicted in Scheme 1, which mainly involved two steps--crosslinking and swelling. Briefly, bisacrylate modified Ad as the crosslinker 17 , 4,7-di(thiophen-2-yl)benzo[c] [1,2,5] thiadiazole (BTH) as the fluorescent energy acceptor 28 and UV photoinitiator 2-hydroxyethyl-2methylpropiophenone were dissolved in methacrylate (MA) as one of the monomers. Then, to stabilize these hydrophobic components, surfactant (TWEEN 80) was added, together with the second hydrophilic monomer acrylamide (AM) in aqueous solution.…”

“…Letter / Cluster / New Tools Template for SYNLETT Thieme mechanochemiluminescence (bis(adamantyl)-1,2-dioxetane, Ad 17 ).…”

“…reactions with spectroscopic signals are advanced in illuminating the fracture mechanics of tough soft materials with high resolution. Typical mechanophores and the corresponding visualized outputs include mechanically induced color change (such as spiropyran, 13 diarylbibenzofuranone, 14 and more), induction or fading of fluorescence (such as rhodamine, 15 anthracene dimers 16 ), and mechanochemiluminescence (bis(adamantyl)-1,2-dioxetane, Ad 17 ).…”

Self-Healing Hydrophilic Porous Photothermal Membranes for Durable and Highly Efficient Solar-Driven Interfacial Water Evaporation

“…With the progress in supramolecular chemistry and synthetic chemistry, various self-healing polymers that are capable of healing damage by themselves to restore the mechanical and/or chemical properties have been Page 2 of 31 CCS Chemistry 3 successfully synthesized. [20][21][22][23] In addition, by combining self-healing polymers with functional materials, plenty of self-healing functional materials with superhydrophobicity, [24][25][26][27] antifouling, [28][29][30] electrical conductivity, [31][32][33][34] sensing, [35][36][37][38][39][40][41] and other functions [42][43][44][45][46][47][48][49][50] have been fabricated, significantly decreasing maintenance costs and promoting safety, reliability, and service life. The design and fabrication of self-healing materials with photothermal and water transportation capabilities that can repair their functions upon damage would be a judicious solution to increase the stability and service life of solar-driven interfacial evaporators.…”

Polymeric materials reinforced by noncovalent aggregates of polymer chains

“…[2][3][4] The first lies in intrinsic regulation of the configuration of poly-mer chains and the structure of polymer networks to restrain the mobility of polymer chains upon load, such as alignment and crystallization of polymer chains, interpenetration of polymer networks, double-network crosslinking, and so forth. [5][6][7][8][9][10][11][12][13] The second relies on the extrinsic incorporation of rigid nanofillers into the polymer matrices, wherein the nanofillers include inorganic and organic nanomaterials, such as silica, [14][15][16] clays, [17][18][19][20] glass fibers, [21] carbon nanomaterials, [22][23][24][25][26] cellulose nanocrystals, [27,28] and so forth. [29][30][31] The as-described intrinsic and extrinsic strategies can be combined to synergistically enhance the mechanical performances of the resultant polymer composites.…”