The interfacial microcracks in the resin matrix composites are difficult to be detected and repaired. However, the self-healing concept provides opportunities to fabricate composites with unusual properties. In the present study, photothermal conversion Ag-Cu2S nanoparticles were immobilized onto poly(p-phenylene benzobisoxazole) (PBO) fibers via a polydopamine chemistry. Benefitting from the photothermal effects of Ag-Cu2S, the obtained PBO fibers (Ag-Cu2S-PBO) efficiently converted the light energy into heat under Xenon lamp irradiation. Then, single PBO fiber composites were prepared using thermoplastic polyurethane as the matrix. It was found that the interfacial damage caused by single fiber pull-out was simply self-healed by Xe light irradiation. This wonderful interfacial damage self-healing property was mainly attributed to the in situ heating generation via photothermal effects of Ag-Cu2S in the composite interface. This paper reports a novel strategy to construct advanced composites with light-triggered self-healing properties, which will provide inspiration for preparing high performance composite materials.
Inorganic photochromic material is an available medium to obtain optical information storage. The photochromic property of the inorganic material is mainly from the defects of the host. However, the formation of defects in the host is uncontrollable, in particular, the revisable formation and removement of defects are difficult. Thus, there are few inorganic materials with the revisable photochromism upon the entire light stimulation. Therefore, it is an urgent need to find a suitable approach to design inorganic photochromic materials. Here, the photochromic PbWO4:Yb3+, Er3+ ceramic was designed with the help of valence state change of W6+ → W5+ and Pb2+ → Pb4+. Upon the 532 nm laser stimulation, the photochromism of the PbWO4:Yb3+, Er3+ ceramic was obtained based on the Pb2+ + hν (532 nm) → Pb4+ + 2e- and W6+ + e- + hν (532 nm) → W5+ reaction, resulting in the optical information writing. Under the stimulation of an 808 nm laser, the written optical information was erased based on the W5+ + hν (808 nm) → W6+ + e- and Pb4+ + 2e- + hν (808 nm) → Pb2+ reaction. In addition, the photochromism-induced upconversion emission modification was obtained in the PbWO4:Yb3+, Er3+ ceramic, realizing the effective and nondestructive reading out of optical information. The cyclic experiment demonstrated a good reproducibility of both photochromism and upconversion emission modification, exhibiting the potential application of the PbWO4:Yb3+, Er3+ ceramic as the optical data storage medium.
Abstract Converting poly(ethylene terephthalate) (PET) into metal–organic frameworks (MOFs) has emerged as a promising innovation for upcycling of waste plastics. However, previous solvothermal methods suffer from toxic solvent consumption, long reaction time, high pressure, and high temperature. Herein, a mechanochemical milling strategy was reported to transform waste PET into a series of MOFs with high yields. This strategy had the merits of solvent‐free conditions, ambient reaction temperature, short running time, and easy scale‐up for large‐scale production of MOFs. The as‐prepared MOFs exhibited definite crystal structure and porous morphology composed of agglomerated nanoparticles. It was proven that, under mechanochemical milling, PET was firstly decomposed into 1,4‐benzenedicarboxylate, which acted as linkers to coordinate with metal ions for forming fragments, followed by the gradual arrangement of fragments into MOFs. This work not only promotes high value‐added conversion of waste polyesters but also offers a new opportunity to produce MOFs in a green and scalable manner.
In the title complex, [La(C(6)H(4)NO(3))(C(2)O(4))(H(2)O)(2)](n), the La(III) ion is coordinated by eight O atoms from two 2-oxido-pyridinium-3-carboxyl-ate ligands, two oxalate ligands and two water mol-ecules in a distorted bicapped square-anti-prismatic geometry. The carboxyl-ate groups link adjacent La(III) ions, forming two-dimensional layers that are further linked by N-H⋯O and O-H⋯O hydrogen bonds.
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