Polymer Journal

Saeki, Akinori

doi: 10.1038/s41428-020-00399-2pmid: 32873989

Light is a form of energy that can be converted to electric and chemical energies. Thus, organic photovoltaics (OPVs), perovskite solar cells (PSCs), photocatalysts, and photodetectors have evolved as scientific and commercial enterprises. However, the complex photochemical reactions and multicomponent materials involved in these systems have hampered rapid progress in their fundamental understanding and material design. This review showcases the evaluation-oriented exploration of photo energy conversion materials by using electrodeless time-resolved microwave conductivity (TRMC) and materials informatics (MI). TRMC with its unique options (excitation sources, environmental control, frequency modulation, etc.) provides not only accelerated experimental screening of OPV and PSC materials but also a versatile route toward shedding light on their charge carrier dynamics. Furthermore, MI powered by machine learning is shown to allow extremely high-throughput exploration in the large molecular space, which is compatible with experimental screening and combinatorial synthesis.

Xia, Lei; Zhang, Ze; You, Ye-Zi

doi: 10.1038/s41428-020-0394-xpmid: N/A

Ring-opening polymerization of lactones has served as one of the most resourceful and versatile methods for the production of polyesters. However, the 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 benzyl alcohol or butyl alcohol as an initiator under visible light. The wavelength of the light could be easily adjustable by applying different photocatalysts. Moreover, radical species are generated concurrently during the electron transfer processes; as a result, simultaneous living/controlled cationic ring-opening polymerization of lactones and reversible addition–fragmentation chain transfer radical (RAFT) polymerization can be performed using hydroxy group capped trithiocarbonate to produce hybrid block copolymers.

Song, Bin; Zhang, Li; Yin, Honglei; Liang, Hongming; Zhang, Jinwei; Gu, Haibin

doi: 10.1038/s41428-020-00398-3pmid: N/A

Through the use of N-[2′-ferrocenylformamido-ethyl]-cis-5-norbornene-exo-2,3-dicarboximide (NFc) and N-[2′-adamantylformamido-ethyl]-cis-5-norbornene-exo-2,3-dicarboximide (NAd), we report the fabrication of two novel supramolecular norbornene monomers, NFc@β-CD and NAd@β-CD, through β-cyclodextrin (β-CD)/ferrrocene(Fc)- and β-CD/adamantane (Ad)-based host–guest complexation. The formation and structure of the two monomers were verified by various techniques, such as 1H and 13C NMR, 2D NOESY, IR and UV–vis spectroscopic methods. The ROMP (ring-opening metathesis polymerization) feasibility of the two supramolecular monomers was further confirmed by the successful preparation of two homopolymers (P(NFc@β-CD) and P(NAd@β-CD)) and two diblock copolymers (PNFc-b-P(NAd@β-CD) and P(NFc@β-CD)-b-P(NAd@β-CD)). The prepared polymers were adequately analyzed using 1H and 13C NMR, IR, UV–vis, end-group analysis and GPC methods. Based on the obtained results, we believe that (1) both supramolecular monomers exhibited “living” and “controlled” ROMP reactions; (2) the β-CD/Fc and β-CD/Ad inclusion complexes were not disassembled during the ROMP reactions of the two supramolecular monomers; and (3) the functional groups of β-CD had a negligible effect on the catalytic activity of the third-generation Grubbs’ catalyst. In short, this work indicated that the direct ROMP of β-CD-containing supramolecular monomers was a feasible route for preparing supramolecular polynorbornene-based homopolymers and copolymers, and this route is expected to have great potential for the preparation of various supramolecular polynorbornenes and functional materials.

Matsumoto, Takuya; Yorifuji, Miyabi; Sugiyama, Yuya; Nishino, Takashi

doi: 10.1038/s41428-020-00402-wpmid: N/A

Poly(vinyl butyral) (PVB) is widely accepted as an adhesive for glass substrates within the automobile windows. In this work, we suggested and performed butyralization of poly(vinyl alcohol) (PVA) under supercritical carbon dioxide (sc-CO2) and investigated not only the structure and mechanical properties of the obtained PVB but also its adhesion properties under various conditions, comparing this PVA with other PVBs prepared in the solution and swollen states. The conversion ratio of butyralization under sc-CO2 was larger than that in the swollen state and lower than that in the solution state and exhibited a sufficient material performance as the adhesive for glass substrates. The Young’s modulus and tensile strength of PVB under sc-CO2 were higher than those of the other PVBs. The mechanical properties of the PVB prepared under sc-CO2 have no correlation to the modification ratios because sc-CO2 penetrated into the amorphous region of the PVA and preferentially modified its hydroxyl groups. Furthermore, the adhesive strengths of all the obtained PVBs increased, and under a high-humidity atmosphere, the adhesive strength of the PVB prepared under sc-CO2 was the largest. The humidity resistance of the PVB adhesive prepared under sc-CO2 was proven.

Nguyen, Thu Ha; Tran, Thi Thuy; Kawahara, Seiichi; Ougizawa, Toshiaki

doi: 10.1038/s41428-020-00403-9pmid: N/A

Natural rubber-grafted polyaniline with a nanomatrix structure was prepared and characterized. The graft copolymerization of aniline on natural rubber was performed in the latex stage. Factorial experimental design and univariate experiments were used to evaluate the effect of the factors on the conversion of aniline in the graft copolymerization. The structure of the products was characterized through 1H-NMR spectroscopy. The thermal properties, electrical conductivity, and morphology of the products were investigated. The results from the factorial experimental design showed that reaction temperature was the most important factor affecting the conversion, pH was the next most important, and the other factors were relatively unimportant. Polyaniline was confirmed to graft onto natural rubber and form a nanomatrix structure in the resulting material. The thermal properties and electrical conductivity of natural rubber-grafted polyaniline with a nanomatrix structure were improved compared to those of a polyaniline/natural rubber blend with an island-matrix structure.

Yamamoto, Kazuki; Saito, Ibuki; Amaike, Yunosuke; Nakaya, Toshimi; Ohshita, Joji; Gunji, Takahiro

doi: 10.1038/s41428-020-0386-xpmid: N/A

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 to compare their hydrophilicity and water desalination properties. Water contact angle experiments on the film surfaces revealed that the BTES-VP-derived film was more hydrophilic than the BTES-VB-derived film. Density functional theory calculations of the monomer structures also suggested that BTES-VP is more polar and has a larger dipole moment than BTES-VB. 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.

Doi, Naoki; Yamauchi, Yukinori; Ikegami, Ryo; Kuzuya, Masayuki; Sasai, Yasushi; Kondo, Shin-ichi

doi: 10.1038/s41428-020-0387-9pmid: N/A

Polymer micelles with a tunable drug release would be suitable for the concept of drug delivery system. We constructed photo-responsive polymer micelles from amphiphilic block copolymers. The polymer micelles were synthesized by mechanochemical solid-state copolymerization of poly[N-(2-hydroxypropyl)methacrylamide] (PHPMA) and 4,5-dimethoxy-2-nitrobenzyl methacrylate as a photosensitive moiety. The above mechanochemical solid-state copolymerization was performed by vibratory-ball milling at 30 Hz in a nitrogen atmosphere with the use of an agate vessel and an agate ball to yield amphiphilic block copolymers (PHPMA-b-PDNMA). Spherical polymer micelles were formed by the self-assembly of PHPMA-b-PDNMA. The diameter of the PHPMA-b-PDNMA micelles was in the range of 130-200 nm. The PHPMA-b-PDNMA micelles loaded with the antitumor drug 5-fluorouracil (5-FU) showed photo irradiation induced time-dependent release of 5-FU with an associated decrease of micellar size. The drug release profile of the PHPMA-b-PDNMA micelles followed a clear sigmoid curve. Our approach provides a controlled drug release system through the use of photo-responsive polymer micelles, accompanied by the gradual decrease of micellar size.

Nguyen, Thi Lien; Katayama, Risa; Kojima, Chie; Matsumoto, Akikazu; Ishihara, Kazuhiko; Yusa, Shin-ichi

doi: 10.1038/s41428-020-0390-1pmid: N/A

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). The effect of sonication time and the solubilized concentration of water-soluble fullerene C60 on the amount of generated 1O2 was studied. Singlet oxygen sensor green was used to confirm the generation of 1O2. 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.

Wu, Jianbing; Guo, Wenjun; Zhang, Lixiang; Wang, Yongfeng; Liu, Leigen; Wang, Wei; Sun, Yinyin; Tao, Jin; Wang, Xiaoqin

doi: 10.1038/s41428-020-0392-zpmid: N/A

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. Polyethylene glycol, a type of synthetic polymer that is widely used in the pharmaceutical industry as a formulation excipient, was utilized to induce silk fibroin to self-assemble into nano- and microspheres. The addition of a certain amount of salt in the blending solution with subsequent titration into ethanol could improve the size dispersion, yield, and crystalline β-sheet structure (silk II) compared to those prepared without salt addition during preparation. Silk microspheres prepared in the presence of salts were less porous and more homogeneous in size than those prepared in the absence of salts.

Shida, Naoki; Nishimi, Honoka; Asanuma, Yuki; Tomita, Ikuyoshi; Inagi, Shinsuke

doi: 10.1038/s41428-020-0388-8pmid: N/A

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, suggesting that the polymer product has a narrower band gap than the precursor polymer.