Research articles

Polyhydroxyalkanoate copolymers of (2R,3R)-3-hydroxy-2-methylbutyrate and (R)-3-hydroxybutyrate [P(3H2MB-co-3HB)] with various comonomer compositions were biosynthesized using recombinant Escherichia coli. Furthermore, solvent fractionation of P(3H2MB-co-3HB) was performed to obtain copolymers with narrow comonomer-unit compositional distributions. The melting temperature (T_m) of P(3H2MB-co-3HB) as a function of the comonomer content indicated isodimorphism of the copolymer. The fast crystallization behavior of P(3H2MB) was maintained even when it was copolymerized with 3HB. The P(80 mol% 3H2MB-co-3HB) copolymer, with a T_m close to that of P(3HB), exhibited faster crystallization behavior than the P(3HB) homopolymer.

A mesh-like crystal structure of ultrahigh molecular weight polyethylene (UHMWPE) films is achieved through a two-step biaxial stretching mode to construct a planar-oriented crystal network. This mesh-like crystal network structure was investigated through scanning electron microscopy (SEM) and 1-dimensional wide-angle X-ray diffraction (1D-WXRD). The corresponding in-plane thermal conductivity increases to 7.3 W.m/K at a total draw ratio of 25, much higher than samples with single temperature biaxial stretching modes.

Simulation-based materials informatics shows that when the detachment energies of the odd-numbered amino acids with –COOCH₃ are high, and when the detachment energies of the even-numbered amino acids with –CH₃ are high, the binding free energy between the peptide and PMMA resin becomes high. From this guideline, W, R, and E are found to be effective as odd-numbered amino acids, and W and R are found to be effective as even-numbered amino acids for strong adhesion to PMMA resin.

The self-assembly process of a lysine derivative (Fmoc-Lys) in water-DMSO mixtures was investigated by time-resolved static and dynamic light scattering, small-angle X-ray scattering, optical microscopy, and scanning electron microscopy. The experimental results indicated liquid-liquid phase separation caused by the addition of water to the DMSO solution of Fmoc-Lys and the formation of spherical droplets of the phase-separating concentrated phase. In the colloidal phase-separating solution, the concentrated phase droplets did not grow through the Ostwald ripening process, but transformed to a crystal phase after a long lag phase.

To improve the 3-dimensional (3D) printed quality of bio-based composites, bamboo fibers were chemically modified via a two-step reaction. In the first step, NCO groups (of a diisocyanate) were grafted onto the surface of fibers, which were subsequently reacted with a polyol. Afterward, 3D-printed objects were produced using these fibers. The advantage of using treated fibers was reflected in the improved mechanical performance of the obtained 3D specimens.

In this work, we employed Carbothane® electrospun matrices (PCU) for lysine surface modification, using oligomers obtained from allyl glycidyl ether (AGE) reaction as spacers. The incorporation of AGE oligomers significantly reduced the nonspecific protein adsorption, while further modification with lysine led to a more pronounced decrease. The lysine-modified matrices presented increased plasminogen adsorption capacity and in vitro clot lysis ability, confirming the plasminogen adsorption selectivity and thus improving the hemocompatibility behavior of these matrices.

The construction of a deep learning model and visualization of judgment regions were conducted for wide-angle X-ray diffraction and small-angle X-ray scattering images of aliphatic polyesters. The classification models based on convolutional neural networks (CNNs) for the X-ray images to predict the types of polymers and several crystallization temperatures were successively constructed. The judgment regions of the X-ray images used by the CNNs were visualized using the Grad-CAM, LIME, and SHAP methods. This result may contribute to developing important features in deep learning models, such as the recognition of structure–property relationships.

Composites of fluoropolymer (FKM) and nano-carbon fillers have been considered as sealing materials for hydrogen fuel storage. We here characterize, structurally and dynamically, FKM chains adsorbed on single-walled carbon nanotubes (SWCNTs) and carbon black (CB), which were prepared by a solvent leaching method.

Diblock copolymers consisting of flexible polystyrene and semiflexible poly(n-hexyl isocyanate), P(S-b-HIC)s, were prepared by anionic polymerization, followed by SEC fractionation. The microphase-separated structures of two P(S-b-HIC)s with Φ_PHIC = 0.18 and 0.31, were investigated by TEM, SAXS and WAXS. Both two P(S-b-HIC)s exhibited hexagonally packed cylindrical structures but different cross-sectional shapes, namely, P(S-b-HIC)-0.18 has a round-shaped cross-section, while P(S-b-HIC)-0.31 has a distorted one. The latter could originate from the liquid crystalline structures of the PHIC blocks in cylindrical domains, which align obliquely to the interface of the domains.

A transparent film with photoactive antiviral functions and minimal degradation over time was easily obtained by uniformly dispersing the phenoxy-substituted phthalocyanine zinc (PPcZn) in the cellulose acetate film. This film produced singlet oxygen (¹O₂) upon visible light irradiation, and the production capacity of ¹O₂ was maintained even when the film was exposed to indoor lighting for 6 months.

We prepared monolayer- and bilayer-type AuNP-containing collagen coatings as a photosensitive cell scaffold in a photoinduced in situ cell detachment system. The monolayer type of AuNP/collagen coatings showed efficient cell detachment with cell damage and may be applied to remove undesired cells. The bilayer-type AuNP/collagen coatings may be applied to collect desired cells because of the low cell damage. We demonstrated the sorting of visually changed transfected CHO-K1 cells and human-induced pluripotent stem cell-derived cardiomyocytes using our system, which is useful for genome editing and regenerative medicine, respectively.

This study presents a simple and general platform for the efficient loading and delivery of proteins using a methoxy-poly(ethylene glycol)-block-poly(L-phosphotyrosine) (mPEG-b-PpY)-templated calcium phosphate (CaP) hybrid nanoparticle. Recombinant proteins bearing a histidine tag can be conveniently loaded onto the hybrid CaP nanoparticles doped with Zn²⁺ (CaP-Zn) by coordination. Nanoparticle can be protected the protein from proteolytic degradation and effectively delivered to intracellular spaces. This work may open up opportunities for intracellular delivery of recombinant protein therapeutics.

Alcohol end-functionalized poly(3-hexylthiophene) (P3HT-OH) is a high-value material mainly used for the generation of P3HT-containing block copolymers. However, the synthesis of P3HT-OH has required effort-intensive postpolymerization modifications and additional protecting group techniques. Thus, to overcome the issue, we developed the direct one-pot synthesis of P3HT-OH by Suzuki-Miyaura catalyst-transfer polycondensation. Mild reaction conditions with good functional group tolerance allowed the preparation of well-defined P3HT-OH without protective groups or postmodification processes. Under optimized reaction conditions, low to high molecular weight P3HT-OH can be prepared with high precision and productivity.

Preparation and characterization of poly(2,6-dimethyl-1,4-phenylene)oxide (PPO) films exhibiting the cocrystalline phase with carvacrol, a relevant natural antimicrobial, are reported. The relative intensity and linear dichroism of two O–H out-of-plane deformation peaks (at 698 and 717 cm⁻¹) of carvacrol can be rationalized by assuming that these peaks are due to isolated and hydrogen-bonded guest molecules, respectively, and by slower desorption of carvacrol when included as isolated molecules in the cavities of the polymer host crystalline phase.

Fluoride anions-catalyzed cage scrambling and gelation of POSS-pendant random copolymers was investigated. A series of POSS-pendant random copolymers was prepared using POSS-containing methacrylates and several vinyl monomers. FT-IR, solid-state ²⁹Si-NMR, and swelling experiments of the gelation products showed that the pendant POSS groups underwent intermolecular cage-scrambling reaction, which proceeds via transient siloxane cleavage. Chloride and bromide anions also catalyzed the scrambling reaction under modified reaction conditions. Gelation properties depended on various factors such as the comonomers, reaction solvents, vertex substituents, POSS contents, and catalyst feeds.

For n-type organic semiconductors, low thermoelectric conversion properties are an issue that needs to be resolved, moreover current manufacturing methods are not compatible with printing technology. In this communication, we report the systematic preparation of carbon nanotube (CNT) sheets containing dopant polymers using a drop-casting method that enhances thermoelectric performance. The inclusion of 1,2-diphenylhydrazine as a secondary dopant significantly improved the ZT value of poly(N-vinyl-2-pyrrolidone)-poly(vinyl alcohol) graft copolymer/CNT, from 5.26 × 10⁻³ for the undoped system to 1.34 × 10⁻². The developed approach, which is expected to provide on-demand manufacturing through printed electronics technologies.

A fluorescent microarray comprising polythiophene-based chemosensors functionalized with pyridinium boronic acid has been developed for the detection of the components of sake such as glucose and pyruvate. The sensor microarray was fabricated on a glass chip for on-site detection utilizing imaging analysis and pattern recognition. The selected four nondiluted sake samples were discriminated by the cross-reactive response pattern. Moreover, the facile chemosensor array realized the prediction of unknown concentrations of glucose and pyruvate in the diluted sake, which indicated its usability for drink analysis.

The aggregation behaviors of a diblock copolymer and a triblock copolymer of poly(2-ethyl-2-oxazoline) (PEOX) and polyethylene oxide (PEO) in aqueous solutions were investigated mainly by static and dynamic light scattering and infrared spectroscopy. PEOX is a thermoresponsive polymer that is soluble in water at room temperature, but insoluble above 60 °C, and it forms aggregates with poly(methacrylic acid) (PMAA) by using intermolecular hydrogen bonds.

A novel superabsorbent polymer crosslinked with diacylhydrazine DC-SAP was prepared. A very-high water uptake (ca. 80,000%) was observed in DC-SAP at a crosslinking ratio of 1%. The swollen gel was instantly (<5 s) solubilized by treatment with a small amount of sodium hypochlorite solution. A commercially available bleacher could also be used for the solubilization of DC-SAP. Despite the high degradability of DC-SAP, it exhibited high chemical and thermal stability. The decomposition product is composed of pure poly(sodium acrylate), which is extremely safe substance.

UV light-induced polymerization is one of the most efficient methods to produce pressure-sensitive adhesives in lamination processes, as it is simple and easily scalable. Acrylates and/or methacrylates are typically used as the main components, however, O₂ inhibitors are needed, which increases the final cost. In this work, we exploit the oxygen insensitivity of thiol-click reactions, evaluate their potential for use in fast and inexpensive UV curable resins, and demonstrate the design of a formulation with competitive adhesive performance compared to conventional acrylic PSAs.