Original Article in 2020

In this study, high birefringent acetylene group containing azobenzene-based polymers were synthesized as materials for rewritable green-laser holograms, and their properties were evaluated. Birefringence change of polymer, which has an absorption wavelength suitable for green laser (532 nm), is 0.018. The diffraction efficiency of polymer was 72% under low-energy irradiation (7 J/cm²). These results show that the hologram recording material made in this study with high birefringent azobenzene are stable, without undergoing decomposition even when repeated recording and rewriting were performed.

Isotactic poly(N,N-diethyl acrylamide) (i-PDEAA) was prepared by ytterbium triflate/H₂O-catalyzed radical polymerization in the presence of an organotellurium chain transfer agent. i-PDEAA single crystals were successfully grown from solution using a mixture of methanol and diethyl ether as the solvent. Selected-area electron diffraction patterns obtained by transmission electron microscopy provided clear information about the unit cell and suggested polymorphisms of the i-PDEAA crystals. Lattice constants of the two crystal forms were reported.

The role of alcohol in the Yb(OTf)₃- and Y(OTf)₃-catalyzed stereoselective radical polymerization of acrylamides is clarified. The coordination of two equivalents of alcohol to the metal triflate generates a complex, which increases both the polymerization rate and stereocontrol compared to those without an alcohol. The importance of hydroxyl groups of the alcohol is suggested by the observed secondary isotope effect for the rate enhancement. The conditions are highly compatible with those for organotellurium-mediated radical polymerization, and the dual control of molecular weight and tacticity is successfully achieved.

Functional micellar nanocarriers for codelivery of doxorubicin (DOX) and caffeic acid phenethyl ester (CAPE) were successfully developed via coassembly of PEO₁₁₃-b-PCL₃₅-b-PEO₁₁₃ and PAA₁₃-b-PCL₃₅-b-PAA₁₃. CAPE was entrapped into the PCL core via hydrophobic interactions, while DOX was loaded in the middle layer through complexation between the amino and carboxylic groups of DOX and PAA. The dual drug-loaded micelles exhibited superior colloidal stability and sustained drug release profiles. The dual drug -loaded system suppressed the proliferation of mouse T-lymphoma L5178Y MDR1 cells more effectively than the single drug-loaded micelles, suggesting a synergistic effect.

This study comprehensively reveal the critical parameters of poly(ethylene oxide) (PEO) in the MD simulation that causes the numerical effect on polymer simulation and the variation of thermodynamics property. The threshold value of total molecular weight of 11,240 g/mol must be satisfied, which leads the polymer that exhibits its steady state bulk properties. For the oligomer system (Mw < 2248 g/mol per chain (50 monomers)), the total chain number must be more than 10 at least. The cooling rate must be lower than 5 × 10¹³ K/min for the structural equilibrium.

This study focuses on employing multilayer melt electrospinning of polymers coupled with a delamination step to obtain nonwoven webs of ribbon-shaped fibers. A coextrusion technique with layer multipliers was used to melt electrospin cylindrical microfibers that have up to 257 alternating layers within each fiber prior to delamination. The bicomponent layered cylindrical microfibers are delaminated using sonication or solvent rinsing to obtain flat nanoribbon fibers, that are 150 nanometers to 200 nanometers thick.

We examined drug release behavior and anticancer efficacy of cyclodextrin-based nanoparticles (CDNPs) containing alpha-mangostin (MGS) in three different type of CDs (α-, β-, and γ-CD). βCDNP containing MGS demonstrated the best anticancer efficacy, while no efficacy was observed for the other CDNPs. Our findings suggested the anticancer efficacy might depend on the drug retention capability in which the interior and surface CDs in the CDNPs relate to the slow and rapid release modes, respectively. We assume the drug retention capability of slow release mode is important for performing the anticancer efficacy.

The microporosity of poly(1-trimethylsilyl-1-propyne) (PTMSP) and poly(4-methyl-2-pentyne) (PMP) is investigated by two independent methods—convenient low-temperature Ar sorption and less commonly used small-angle X-ray scattering (SAXS). The Brunauer–Emmett–Teller-specific surface values obtained for PTMSP and PMP from Ar sorption isotherms correlate with the specific surface values obtained from the SAXS method. The correlation of the specific surface values obtained from fundamentally different methods makes it possible to evaluate the small-angle scattering method as adequate for assessing the microporosity of polymeric materials.

High-molecular-weight (HMW) benzoxazines were synthesized by Mannich condensation with various combinations of bisphenols and diamines, and the mechanical and thermal properties of the polybenzoxazines derived from the HMW benzoxazines were measured by tensile tests and thermogravimetric analysis to investigate the structure-property relationship. Among the polybenzoxazines presented in this work, the PODP-oda film derived from 4,4′-oxydiphenol and 4,4′-oxydianiline showed remarkably good mechanical properties (E = 3.7 GPa, s_b = 125 MPa, and e_b = 4.5%) and thermal stability (T_d5 = 332 °C).

A hyperbranched polymer (HBP) additive is used to explore short-range molecular motions in the glassy state of crosslinked epoxy amine networks via subambient β relaxations as measured by dynamic mechanical thermal analysis. Increasing HBP addition increased modulus and stress, while reducing yield strain. Pre-reaction using an isocyanate linkage between the HBP and network comparatively reduced modulus while increasing stress and strain. Glassy state mobility of the epoxy amine network as a result of HBP addition, could be directly related to many changes in mechanical properties observed.

A gyroid nanostructured soft polymer film was developed by the co-organization of two types of amphiphile zwitterion monomers and a suitable acid into a bicontinuous cubic liquid-crystalline phase and subsequent in situ polymerization. The obtained polymer film showed a high ionic conductivity of 1.27 × 10^–2 S cm^–1 at a relative humidity of 90%.

The mechanism of intense autopolymerization reaction of 2-bromo-3-methoxythiophenes spewing brownish gas was clarified from UV-Vis, ESR, GC/MS, elemental analysis, NMR, and FT-IR spectroscopy. The reaction contained the formation of the hydrogen bromide gas during the autopolymerization. The gas induced the cleavage of the methoxy group on the thiophene ring to form the methyl bromide gas as the side reaction. This work provides an important guide for the application of the autopolymerization of thiophene derivatives to design new polymer materials.

Self-healable and cell-compatible polyurethane elastomers cross-linked by charge-transfer complexes between electron-rich pyrene (Py) and electron-deficient naphthalene diimide (NDI) were fabricated by simply blending two linear polymers with Py or NDI as a repeating unit. The elastomers with different blend ratios self-healed damage over 1 day in mild conditions, including in air and water at 30–100 °C. The good cell compatibility of the polyurethane elastomers was demonstrated by culturing two kinds of cells on the thin film substrates.

A surface-controlled cooperatively rearranging region (SCC) model mimics the segmental dynamics of supercooled liquids. By introducing surface/interface effects into the SCC model, the size-dependent dynamics of nanosized polymer materials with various geometries were predicted. The calculated glass transition temperature (T_g) and fragility for filled spheres of polystyrene coincided qualitatively with experimental observations. The results also showed that T_g(filled sphere) > T_g(filled fiber) > T_g(free-standing film) when compared at the same surface area to volume ratio, whereas for fragility, the opposite trend was found.

The fabricated polymeric liquid crystal beads surfaces consist of aligned rhodamine B-derived active sites possess capacity of sensing copper ions in tested solutions. The color of the beads changed to deep pink while copper ions exist in the solutions, whereas it can be easily recycled by adding aqueous ammonia, indicating the beads applied as a powerful monitoring tool.

The structural evolution of β-iPP with two different supermolecular structures during the simultaneous biaxial stretching process was studied. The two samples showed different structural evolution modes. β-hedrites exhibited violent cavitation behavior during the initial stage of deformation, but in the late stages of stretching β-hedrites formed numerous dense regions, which hindered microvoid formation and led to a poor pore size distribution. Conversely, β-spherulite generated abundant microfibrillar structures, and abundant microvoids were formed, forming a membrane with a superior pore size distribution.

Bacteria possibly capable of polyhydroxyalkanoate synthesis from lignin were investigated by genomics and chemistry of biomaterials. Aquitalea sp and Ralstonia pickettii isolated from a blackwater lake rich humic substances, showed great potential to be developed for this purpose. Canonical lignin degradation pathways, such as protocatechuate 4,5-dioxygenase-dependent pathway, CoA-dependent non-β-oxidation pathway of ferulic acid and β-ketoadipate pathway were mapped in their genomes. In addition, traces of P(3HB) were found when using vanillic and gallic acids as sole carbon source, which indicates that the downstream β-ketoadipate pathway is functional.

Polyhydroxyalkanoate (PHA) is a biopolyester similar to some commodity plastics. The production cost of PHA is high partly due to the cost of feedstock. Spent bleaching clay (SBC) is a byproduct of the palm oil refining process. Adsorbed residual oil in SBC was successfully utilized by Cupriavidus necator Re2058/pCB113 in shaken flask culture for PHA production. Both the SBC and the resulting PHA were characterized by SEM, rheometer, TGA, DSC, GC and ¹H-NMR to demonstrate the production of a PHA copolymer containing 3-hydroxyhexanoate.

Inspired by the natural spinning process, we developed an aqueous spinning system with a citrate/polyethylene glycol buffer for highly extensible silk fibers. This system enabled tuning of the induction of crystallization through the buffer conditions.

Carboxylated butyl rubber derivatives were obtained by reacting the isoprene units in the isobutylene copolymer with alkylmercaptanoic acids comprising alkyl spacers of different lengths. The yield of the reactions varied from 80 to 90% for direct reaction of the copolymer containing 1,4-isoprene units, but increased to 90–98% if the 1,4-units were isomerized to terminal alkenes prior to the reactions.