Photomechanical molecular crystals have garnered attention for their ability to transform light into mechanical work, but difficulties in characterizing the structural changes and mechanical responses experimentally have hindered the development...

Photoisomerization of molecules dissolved in a polymer film can modulate its properties. In a previous paper (Mostafavi, S. H.;et al. Macromolecules 2018et al. Macromolecules , 51, 2388et al. Macromolecules −2394, it was found that the ultraviolet light-induced photoisomerization of spiropyran dopants could substantially increase adhesion to a glass surface. In this work, a different photochromic reaction, the visible-light-induced cyclization of a donor−acceptor Stenhouse adduct (DASA), leads to the opposite effect: the deadhesion of a polystyrene film from a clean glass surface. Measurements of the shear and pull-off adhesion strengths before and after visible irradiation show a light-induced decrease of 20−30%. The time required for delamination in water shows an even more dramatic decrease of 90%. Changes in the water contact angle and other measurements suggest that molecular-level noncovalent interactions between the polymer and glass are weakened after photoisomerization, possibly due to the molecular contraction of the DASA that disrupts the interaction between its amine groups and the surface silanols. The ability to reduce polymer adhesion using visible light enables the controlled release of dye molecules from a glass container, where these have been stored as a dry powder, into an aqueous solution. Embedding photochromic molecules in a polymer can lead to new effects that may have practical applications in stimuli-responsive materials.

CVD graphene has attracted a great deal of interest from both academia and industry. The strong motivation to commercialize high quality CVD graphene films and related devices has been restricted by the lack of a cheap, efficient, clean and reliable graphene transfer process. In this article, we report a novel graphene transfer technique which provides a route to high-throughput, reliable and economical transfer of graphene without introducing large cracks and residue contamination from polymers, such as PMMA or magnetic impurities. The transferred graphene was thoroughly characterized with Raman spectroscopy, Atomic Force Microscopy, and X-ray photoelectron spectroscopy. Fabricated large area graphene-based field effect transistors exhibited high mobilities, which were about 2 times higher than those for devices prepared with graphene transferred by the conventional wet transfer method. This new graphene transfer technique has the potential to expedite M

To develop novel succinate dehydrogenase inhibitors (SDHIs), two series of novel N-4-fluoro-pyrazol-5-ylbenzamide and N-4-chloro-pyrazol-5-yl-benzamide derivatives were designed and synthesized, and their antifungal activities were evaluated against Valsa mali, Sclerotinia sclerotiorum, FusaHum graminearum Sehw, Physalospora piricola, and Botrytis cinerea. The bioassay results showed that some of the target compounds exhibited good antifungal activities in vitro against V. mali and S. sclerotiorum. Remarkably, compound 9Ip displayed good in vitro activity against V. mali with an EC 50 value of 0.58 mg/L. This outcome was 21-fold greater than that of fluxapyroxad (12.45 mg/L) and close to that of the commercial fungicide tebuconazole (EC 50 = 0.36 mg/L). In addition, in vivo experiments proved that compound 9Ip has good protective fungicidal activity with an inhibitory rate of 93.2% against V. mali at 50 mg/L, which was equivalent to that of the positive control tebuconazole (95.5%). The results of molecular docking indicated that there were obvious hydrogen bonds and p−π interactions between compound 9Ip and succinate dehydrogenase (SDH), which could explain the probable action mechanism. In addition, the SDH enzymatic inhibition assay was carried out to further prove its mode of action. Our studies suggest that compound 9Ip could be a fungicidal lead to discover more potent SDHIs for crop protection.

Improving the modulation depth and switching speed of electrochromic devices is important for expanding the field of electrochromic functional materials applications. The previous study demonstrates that semiconducting (SC‐) single‐wall carbon nanotube (SWNT) thin film based electrochromic cells with ionic liquid as the electrolyte and metallic (MT‐) SWNT counter electrode can operate with fast switching times in the millisecond range. However, achieving a high modulation depth requires an increasing thickness of the electrochromically active SC‐SWNT layer resulting in a slowdown of the switching time by more than order of magnitude. Here it is reported that milliseconds range switching time can be restored by increasing the thickness of MT‐SWNT thin film counter electrode thus matching the electrochemical capacitances of the two sides of the electrochromic cell while reaching a high modulation depth of 20 dB and high coloration efficiency exceeding 1800 cm2 C−1 at an infrared wavelength of 1770 nm. The results are interpreted in terms of considering the SWNT cell as a supercapacitor with two connected in series electric double layer 3D capacitors associated with two opposing SWNT electrodes.

Advances in the chemical vapor deposition (CVD) growth of graphene have made this material a very attractive candidate for a number of applications including transparent conductors, electronics, optoeletronics, biomedical devices and energy storage. The CVD method requires transfer of graphene on a desired substrate and this is most commonly accomplished with polymers. The removal of polymer carriers is achieved with organic solvents or thermal treatment which makes this approach inappropriate for application to plastic thin films such as polyethylene terephthalate substrates. An ultraclean graphene transfer method under mild conditions is highly desired. In this article, we report a naphthalene-assisted graphene transfer technique which provides a reliable route to residue-free transfer of graphene to both hard and flexible substrates. The quality of the transferred graphene was characterized with atomic force microscopy, scanning electron microscopy, and Raman spectroscopy. Field effect transistors, based on the naphthalene-transfered graphene, were fabricated and characterized. This work has the potential to broaden the applications of CVD graphene in fields where ultraclean graphene and mild graphene transfer conditions are required.

Microcrystals composed of the conjugated organic molecule perylene can be encapsulated beneath single-layer graphene using mild conditions. Scanning electron and atomic force microscopy images show that the graphene exists as a conformal coating on top of the crystal. Raman spectroscopy indicates that the graphene is only slightly perturbed by the underlying crystal, probably due to strain. The graphene layer provides complete protection from a variety of solvents and prevents sublimation of the crystal at elevated temperatures. Time-resolved photoluminescence measurements do not detect any quenching of the perylene emission by the graphene layer, although nonradiative energy transfer within a few nanometers of the crystal–graphene interface cannot be ruled out. The ability to encapsulate samples on a substrate under a graphene monolayer may provide a new way to access and interact with the organic crystal under ambient conditions.

The technique of focused ion beam (FIB) milling is used to cut twodimensional shapes into single crystals composed of the organic semiconductor molecule perylene. The use of an ultrathin Au coating and its removal using a KI/I 2 etchant solution allow the crystal to be imaged in the FIB apparatus while protecting it from electron beam damage. Using this approach, features with a spatial resolution on the order of 130 nm can be created while retaining 90% of the original photoluminescence intensity in the surrounding crystal regions. These proof-of-principle experiments demonstrate that FIB milling could provide a general way to control the nanoscale morphology of organic molecular crystals.