Oriented assembly of metal-organic frameworks and deficient TiO_(2) nanowires directed by lattice matching for efficient photoreversible color switching

The photoreversible color switching system(PCSS)is attracting increasing attention for use in alleviating energy crisis and environmental problems.We report a robust PCSS in which lattice matching enables bottom-up oriented assembly between metal-organic frameworks(MOFs)and inorganic nanocrystals(INCs),two distinct entities that differ drastically in structure and function.Specifically,cubic-phase Prussian blue(PB)of a framework backbone is spontaneously attached to rutile TiO_(2)nanowires in a defined orientation triggered by the lattice matching between the(001)plane of TiO_(2)and the(222)plane of PB.Ultraviolet light irradiation accelerates the photoelectron transport within the oriented TiO_(2)/PB system and enables fast photo switching.The derived TiO_(2)/PB paper can be ranked as one of the best light-printing papers in literature because of its high resolution(∼µm)and capability to be repeatedly written for>100 times without significant loss of contrast.The ultrathin TiO_(2)nanowires are rich in oxygen and Ti vacancies,which allow visible-and sunlight-light printing.Density functional theory calculations suggest that the[Fe(CN)_(6)]^(4−) ligand from the PB attaches preferentially to the(110)surface of TiO_(2)to give the ordered TiO_(2)/PB assembly.The findings demonstrate the strong versatility of particles-mediated assembly in advanced materials design.

Design and synthesis of self-healing polymers

Self-healing polymers represent a class of materials with built-in capability of rehabilitating damages. The topic has attracted increasingly more attention in the past few years. The on-going research activities clearly indicate that self-healing polymeric materials turn out to be a typical multi-disciplinary area concerning polymer chemistry, organic synthesis, polymer physics, theoretical and experimental mechanics, processing, composites manufacturing, interfacial engineering, etc. The present article briefly reviews the achievements of the groups worldwide, and particularly the work carried out in our own laboratory towards strength recovery for structural applications. To ensure sufficient coverage, thermoplastics and thermosetting polymers, extrinsic and intrinsic self-healing, autonomic and non-autonomic healing approaches are included. Innovative routes that correlate materials chemistry to full capacity restoration are discussed for further development from bioinspired toward biomimetic repair.