Original Article in 2023

A series of amphiphilic diblock copolymers (PVA_m-b-PVPi_n: m/n = 82/6, 72/26, and 70/74) with different block lengths of hydrophilic poly(vinyl alcohol) (PVA) and hydrophobic poly(vinyl pivalate) (PVPi) blocks were prepared. PVA_m-b-PVPi_n was synthesized from poly(vinyl acetate)-b-PVPi (PVAc_m-b-PVPi_n) diblock copolymer via selectively hydrolysis. In water, PVA_m-b-PVPi_n formed spherical polymer micelles with a PVPi core and a PVA shell. The hydrodynamic radius, light scattering intensity, and aggregation number of PVA_m-b-PVPi_n increased with increasing PVPi block length. In contrast, the critical micelle concentration was reduced because of stronger hydrophobic interactions.

The conformational relaxation of ethylene-propylene-diene terpolymer (EPDM) chains at the interface with a model filler of quartz was examined by sum frequency generation (SFG) spectroscopy in conjunction with molecular dynamics (MD) simulations. We found that the glass transition temperature (T_g) of EPDM was higher at the interface than in the bulk. Also, the conformational relaxation beyond the T_g was significant for ethylene units, but not for propylene units. This information might be useful in controlling the local conformation and dynamics of polymer chains at the interface.

Microstructure-free strong all-wooden nanocomposites (AWNC) was directly made from the weak raw wood (RW) of paulownia, in which microscale wood fibers and void structures were dismantled into a fully consolidated structure containing nanofibrils (as the reinforcing phase) and noncrystalline cellulose, lignin, and hemicelluloses (as the matrix phase). This direct conversion was carried out through simultaneous chemomechanical densification/downsizing in three steps, including (1) partial delignification, (2) partial dissolution with IL or oxidation with TEMPO and ammonium persulfate (APS), and (3) hot pressing with cyclic pressurizing-depressurizing conditions.

The modification of cellulose nanocrystal film using glycidyl silane compounds was performed with a coating process. Control of the surface structure and functionalization by silylation was achieved. Postmodification using glycidyl groups in silane-modified cellulose nanocrystal was demonstrated.

Copolymers of [2-(acryloyloxy)ethyl]trimethylammonium chloride (AETAC) and acrylamide (AAm) (AETAC-co-AAm) are polyelectrolytes used as flocculants in wastewater purification. Diffusion-ordered dimensional NMR spectroscopy (DOSY) experiments for AETAC-co-AAm samples with M_w ranging from 1.9 to 3.9 million and a polyacrylamide sample with M_w of 1.3 million were carried out in pure D₂O and in D₂O containing 0.1 or 1 M NaCl using an inverse-geometry diffusion-probe system. Projections of the DOSY contour plots onto the diffusion coefficient (D) dimension gave distributions of D for the AETAC and AAm units in the samples. The D values at the maximum point of the distribution (D_p) agreed fairly well with those determined by dynamic light scattering.

We studied the effects of polymer encapsulation of 290-nm-sized Al₂O₃(Al)-coated titanium dioxide (Al-TiO₂) particles on the reflectance and hiding power of an inkjet image printed on a polyethylene terephthalate film. Two different polymer shells with 20–30-nm thickness of a poly(methyl methacrylate) (PMMA) shell and a multilayered shell of PMMA and poly(styrene) (PSt) (PMMA/PSt) were prepared using seeded semicontinuous emulsion polymerizations. The brightness (L*) value of the prints from the PMMA- and PMMA/PSt-encapsulated Al-TiO₂ inks increased compared to bare Al-TiO₂.

Submicron-sized SiO₂/Al₂O₃(Si/Al)-coated titanium dioxide (Si/Al-TiO₂) particles were encapsulated through the emulsion copolymerization of methacrylates using a thermoresponsive polymerizable nonionic surfactant, NE-10. An optimized water-dispersion method was developed to disperse Si/Al-TiO₂ dried powders using an ultrasonic homogenizer, a paint shaker, and a pot mill rotator in the presence of partially neutralized poly(isobutylene-alt-maleic acid). The encapsulation efficiency (F_en) was affected by the monomer and initiator types, NE-10, and sodium dodecyl sulfonate concentrations. F_en > 90% was achieved by a two-step semibatch emulsion copolymerization under optimized conditions.

β-cyclodextrin was immobilized on polypropylene nonwoven fabrics in a simple and mild condition. The prepared composite fabrics showed sustained drug release over 12 h.

Three types of aromatic polyketones bearing tetrakis(nonafluorobutyl)-pterphenylene units were successfully synthesized via nucleophilic aromatic substitution polymerization. In particular, high-molecular-weight polymers were obtained in DMAc. These polymers have water and oil repellency, good thermal stability, and excellent solubility in typical organic solvents such as MEK, THF, CHCl3, and DMAc.

The feasibility of using strongly electron-deficient naphthobispyrazine bisimide (NPI) as a building unit for n-type semiconducting polymers used in all-polymer organic photovoltaics (OPV) cells was investigated. The NPI-based polymers had sufficiently deep LUMO energy levels of ~−3.7 eV and narrow bandgaps of less than 1.5 eV, which matched well energetically with p-type polymers exhibiting wide optical bandgaps. The NPI-based polymers exhibited a clear photoresponse in all-polymer OPV cells blended with PTB7-Th as a benchmark p-type polymer and showed power conversion efficiencies of up to 1.6%.

Ring-opening polymerization of a cyclic dithiocarbonate initiated by arylmethyl triflates, derived from benzyl bromide and bis-, tris-, and tetrakis(bromomethyl)benzenes. Synthesis of star-shaped polymers with cores, transferred from initiators and fluorescent dyes (naphthalene, anthracene, perylene) embedded polymers.

During bulk polymerization, the relative concentration of monomer and polymer changes. When the monomer is liquid and the obtained polymer is a glassy solid, vitrification occurs at some point of the reaction. Herein, we investigate the bulk polymerization of methyl methacrylate, ethyl methacrylate, and butyl methacrylate. We show that, at the vicinity of vitrification, the reaction solution becomes heterogeneous, which results in an apparent phase separation. We discuss polymerization-induced vitrification in conjunction with reaction acceleration (the Trommsdorff effect) and subsequent deceleration (the glass effect).

A novel substituted phenylacetylene with a pendant betulin derivative group was designed and synthesized successfully, The obtained monomer was further polymerized in an achiral catalytic system, and polymer exhibited a strong Cotton effect at the main-chain absorption regions in the circular dichroism spectra. The helical porous material polyphenylacetylene grafted onto the natural product lupane triterpene as a side group exhibits a set of valuable properties with excellent thermal stability, solubility and membrane-forming ability.

PLLA exhibits excellent biocompatibility and biodegradability, but its poor hydrophilicity causes less cell adhesion. To address this issue, the bioactive peptide scaffold was synthesized by PLLA fiber substrate modified with an IKVAV peptide and following heat treatment at 60 °C for regulation of cell adhesive. This scaffold has the potential to serve as an in vitro model for investigating the effect of the ECM on glioblastoma multiforme cells and tumor metastasis in white matter tracts.

PBDTNTz1 and PBDTNTz2 combining naphtho[1,2-d:5,6-d’]bis([1,2,3]triazole (NTz) and benzo[1,2-b:4,5-b’]dithiophene (BDT) were successfully synthesized as wide-band gap polymers for nonfullerene acceptor polymer solar cells. Bulk heterojunction solar cells with inverted structures using PBDTNTz2:ITIC showed a 2.39% power conversion efficiency. The device utilizing PBDTNTz1:ITIC presented a 7.37% PCE with a high V_oc of 0.94 V, an FF of 55.8, and a J_sc of 14.04 mA/cm². OFETs using PBDTNTz1 and PBDTNTz2 showed hole mobilities of 2.2 × 10⁻² cm²V⁻¹s⁻¹ and 5.0 × 10⁻² cm²V⁻¹s⁻¹ with current on/off ratios of 1 × 10⁴ and 9 × 10², respectively.

The emulsion stabilization conditions suitable for nanocellulose-coated microparticle syntheses was investigated by changing the lengths of nanocelluloses. The optimal nanocellulose concentration for stabilizing the emulsion was found to vary with the nanocellulose length, and longer nanocelluloses efficiently stabilized the emulsion at lower concentrations due to the higher viscosity. The emulsions stabilized by shorter nanocelluloses were found to be more suitable for the preparation of fine microparticles because the nanocelluloses effectively covered the surfaces of oil droplets in the emulsions, precluding coalescence.

The interdetector delay volumes (IDV) for multiangle light scattering (MALS) and differential refractometer detectors are essential instrumental parameters affecting reliability and accuracy. However, a reliable and accurate determination method has not yet been established. The paper proposes a method for determining the IDV value. An SEC-MALS setup with the correct IDV value provides more accurate estimates of not only the weight average molar mass and z-average mean-square radius of gyration but also the number average molar mass and differential weight distribution function for polymer samples having narrow and broad molar mass distributions.