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This article reviews an evaluation-oriented exploration of photo energy conversion systems including organic photovoltaics, perovskite solar cells, photocatalysts, and photodetectors. A time-resolved spectroscopy using a gigahertz electromagnetic wave enables rapid screening of potential optoelectronics of organic/inorganic semiconductors and fast finding of their optimal film processing conditions. This approach is further empowered by machine learning that provides a high-throughput virtual screening in the large molecular space. The author discusses a perspective on this evaluation (from fundamental to application) and its effective combination with data science.
Photocontrolled ring-opening polymerization of lactones with the advantages of being inexpensive, green, and noninvasive, is still rarely reported. In this work, we developed a series of composite photoacid generators containing a common photocatalyst and an onium salt to induce the living/controlled cationic ring-opening polymerization of lactones using alcohol compound as an initiator under visible light. The wavelength of the light could be easily adjustable by applying different photocatalysts. Moreover, simultaneous living/controlled cationic ring-opening polymerization of lactones and reversible addition–fragmentation chain transfer radical (RAFT) polymerization of methyl acrylate can be performed using hydroxy group capped trithiocarbonate to produce hybrid block copolymers in one step.
Two novel supramolecular norbornene monomers were prepared according to β-cyclodextrin–ferrocene (/adamantane) host–guest interactions and exhibited both the “living” and “controlled” ROMP characteristics with the aid of the third-generation Grubbs’ catalyst for the construction of corresponding supramolecular homopolymers and diblock copolymers.
Poly(vinyl butyral) (PVB) is accepted as an adhesive to glass substrates. The PVB was prepared through butyralization of poly(vinyl alcohol) under supercritical carbon dioxides. The Young’s modulus and tensile strength of the PVB prepared under supercritical carbon dioxides were higher than those of the PVBs in the preparation method in solution and swollen states. In addition, the PVB under supercritical carbon dioxide possessed higher adhesive strength to glass substrates even under high humid condition, compared with the other PVBs.
Natural rubber-grafted-polyaniline with nanomatrix structure was prepared through graft-copolymerization. The effect of parameters on the graft-copolymerization was investigated using factorial experimental design and univariate experiments. The structural characterization of the resulting materials through NMR spectroscopy confirmed that aniline was grafted on the natural rubber. As observed in TEM image, polyaniline, which covered the natural rubber particles, formed the nanomatrix, and natural rubber particles formed the dispersed phase. The thermal properties and electrical conductivity of natural rubber-grafted-polyaniline were improved by the formation of nanomatrix structure.
Bridged polysilsesquioxanes are promising materials for reverse osmosis membranes because they exhibit robust properties. To investigate the effects of the polarity and rigidity of organic components of the polymer on the water permeability of the membrane, two alkoxysilane monomers, 2,5-bis[2-(triethoxysilyl)vinyl]pyridine (BTES-VP) and 1,4-bis[2-(triethoxysilyl)vinyl]benzene (BTES-VB), were synthesized. Both membranes prepared from BTES-VP and BTES-VB rejected 95–97% of aqueous sodium chloride and displayed water permeances of 1.1 × 10−13 and 8.5 × 10−14 m3/(m2· Pa· s), respectively.
Polymer micelles with a tunable drug release are promising carriers for drug delivery system. It is very important to clarify the correlation between micellar dissociation kinetics and drug release profile on a stimuli-induced deformation of polymer micelles. In this study, photo-cleavable o-nitrobenzyl ester-based amphiphilic block copolymer was successfully designed and prepared by mechanochemical solid-state copolymerization without any solvents and initiators. The self-assembled block copolymer micelles containing anticancer drugs showed sigmoidal decrease of micellar size and released the corresponding drugs depending on the photo-irradiation time.
The generation of singlet oxygen (1O2) by sonicating a water-soluble complex of fullerene/poly(2-methacryloyloxyethyl phosphorylcholine) (C60/PMPC) was investigated for sonodynamic therapy (SDT). 1O2 was generated from C60/PMPC under ultrasonic irradiation, and the amount of 1O2 increased with increasing solubilized C60 concentration and irradiation time. In cell viability tests, after 3 h of incubation, the cell viabilities were 10% and 84% in the presence of C60/PMPC with and without sonication, respectively. This result suggests that C60/PMPC shows a sonodynamic effect, which demonstrates its potential application in SDT.
The present study described a new method with one step to fabricate silk fibroin nano- and microspheres, with the size of spheres and crystalline structure being controllable during processing. Silk microspheres prepared in the presence of salts were less porous and more homogeneous in size than those prepared in the absence of salts (Control). These properties are important not only for the stabilization of particles but also for the controlled release of entrapped drug molecules.
The synthesis of a novel conjugated polymer containing fused pyridinium units in its main chain is reported. A precursor polymer possessing pyridine and tetrafluorophenylene moieties was reacted in the presence of Lewis acid additives to promote the intramolecular nucleophilic aromatic substitution (SNAr) reaction. The polymer reaction with BE3-OEt2 gave a product polymer soluble in polar organic solvents, and the successful formation of fused pyridinium ring structures was spectroscopically confirmed. The electrochemical and optical properties of the synthesized polymers were also investigated.
We prepared the chemically crosslinked, cylindrical thermoresponsive poly(N-isopropylacrylamide) gels with changing the contents of reversible addition-fragmentation chain transfer (RAFT) agent. The environment in the gel was estimated by using a hydrophobic fluorescence probe. While the equilibrium swelling ratios were comparable, the deswelling response became fast as the content of RAFT agent increased with the formation of “bubble pattern”. This result indicates that the PNIPAAm gels prepared by RAFT still have spatial defects. In addition, the cooperative diffusion coefficients in swelling process of the gels prepared by RAFT polymerization were estimated.
