Organic materials with radical characteristics are gaining increasing attention, due to their potential implications in highly efficient utilization of solar energy. Manipulating intermolecular interactions is crucial for tuning radical properties, as well as regulating their absorption bands, and thus improving the photothermal conversion efficiency. Herein, a diradical‐featured organic small‐molecule croconium derivative, CR‐DPA‐T, is reported for highly efficient utilization of solar energy. Upon aggregation, CR‐DPA‐T exists in dimer form, stabilized by the strong intermolecular π–π interactions, and exhibits a rarely reported high‐spin state. Benefiting from the synergic effects of radical characteristics and strong intermolecular π–π interactions, CR‐DPA‐T powder absorbs broadly from 300 to 2000 nm. In‐depth investigations with transient absorption analysis reveal that the strong intermolecular π–π interactions can promote nonradiative relaxation by accelerating internal conversion and facilitating intermolecular charge transfer (ICT) between dimeric molecules to open up faster internal conversion pathways. Remarkably, CR‐DPA‐T powder demonstrates a high photothermal efficiency of 79.5% under 808 nm laser irradiation. By employing CR‐DPA‐T as a solar harvester, a CR‐DPA‐T‐loaded flexible self‐healing poly(dimethylsiloxane) (H‐PDMS) film, named as H‐PDMS/CR‐DPA‐T self‐healing film, is fabricated and employed for solar–thermal applications. These findings provide a feasible guideline for developing highly efficient diradical‐featured organic photothermal materials.

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A novel chemical strategy for fabricating flexible, transparent, and conductive poly(3,4ethylenedioxythiophene) (PEDOT) films with a nanofibrillar morphology by in situ deposition on commercial plastic substrates has been developed. The key points of the strategy include (1) preimplanting surface sulfate groups (SO 4 -) onto the substrate surface by a confined photocatalytic oxidation (CPO) technique, which was critical both for improving the adhesion of the PEDOT with the substrate via static interactions and for inducing polymerization of EDOT onto the substrate surface, and (2) deliberately controlling the nanofibrillar network morphology by means of the reaction recipe and parameters, which was critical for balancing conductivity and transparency. On the basis of this design, with BOPP as a model substrate, PEDOT-BOPP composite films approximately 20 nm in thickness with a transparency as high as 90% and a conductivity of 300 S/cm were obtained. Moreover, XPS data demonstrated that the SO 4 implanted on the substrate surface constituted the primary dopant of the deposited PEDOT, and peeling tests with 3M Scotch adhesive tape proved that the adhesion between the substrate and PEDOT was drastically enhanced. Combined with a photomask, a PEDOT micropattern on the polymer substrate could also be fabricated.

High-pressure deep shale gas reservoirs are usually highly stress-sensitive. When the reasonable production mode of shale gas well is built, the impact of strong stress sensitivity should be fully considered. First, this study calculated the relationship between permeability and formation pressure under different elastic modulus based on the shale lithology of Long Ma Xi formation in Sichuan Basin by testing and analysing the mechanical parameters of the rock. According to numerical simulation result, when the elastic modulus exceeds 14.0 GPa, the stress sensitivity of the matrix will slight affect the cumulative gas production of shale gas. Second, the changing relation between fracture conductivity and permeability with fracture pressure and the time of pressure acts were experimentally studied. The numerical simulation result suggested that the 30-year cumulative gas production considering the stress sensitivity was reduced by 13.5% compared with the 30-year cumulative gas production without considering the stress sensitivity. Finally, the production of different production modes under different stress sensitive characteristics was predicted using numerical simulation method. When the matrix and fractures are fixed with a same stress-sensitive curve, the initial production allocation will not significantly impact the cumulative gas production. When the fractured fractures are subjected to a varying stress sensitive curve, the lower production allocation will result in higher post-production and cumulative gas production.

Thermo-chemical reactions of modified PAN fibers during heat-treatment process were systematically studied by DSC, FT-IR, EA, XPS, etc. Comparing with original PAN fibers, chemical reactions, structures and elemental compositions of fibers modified with potassium permanganate (KMnO4) were all changed at a certain extent. KMnO4 had reduced the activation energy of cyclization reactions, decreased the area and widened the peak of exothermic curve, decreased the velocity of cyclization reaction, increased the oxygen content about 67%, hence increased C-O-C and C=O groups and the core/shell ratio.