Research articles

Chitinous nanofibers (NFs) exhibit a specific physiological activity not observed in the powdered form. Herein, we aimed to develop a cell-adhesive chitinous NF-based flexible hydrogel. The desired cell-adhesive flexible hydrogel was obtained by introducing cationic groups and vinyl polymerizable functional groups on the surface deacetylated chitin NFs as well as copolymerizing it with N-isopropylacrylamide monomer in an aqueous system. Cells adhered to the gel could be detached by cooling to 4 °C. The composite hydrogel fabricated here may be useful as a cell culture scaffold material in regenerative medicine.

Injectable inclusion complex for cerebral aneurysm treatment were prepared by α-cyclodextrin (α-CD) and hydrophobically modified poly(vinyl alcohol) (hm-PVA). The α-CD/hm-PVA inclusion complex with thixotropic properties can easily be injected into the cerebral aneurysm site using a catheter. Due to the recovery of physical crosslinks (hydrophobic and hydrogen bonding interactions), the α-CD/hm-PVA inclusion complex can stably fill in cerebral aneurysms. Finally, stable hm-PVA gel formation enabled embolization of the cerebral aneurysm after α-CD release.

Design of an N-phenyl maleimide derivative bearing an activated NHS ester for radical copolymerization with tert-butoxystyrene to achieve both precise alternating sequence control and functionalization.

Chitin nanofibers were prepared from purified crab-shell chitin particles by repeated high-pressure homogenization in water. AFM images showed that the chitin nanofibers had heterogeneous network structures. X-ray diffraction patterns showed that both the crystallinity index and crystal width of the original α-chitin decreased by nanofibrillation. Solid-state ¹³C-NMR spectra showed that all C6–OH groups had the gauche–gauche conformation. The degree of N-acetylation increased from 0.83 to 0.98 by nanofibrillation, while the weight-average molar masses of the original chitin and chitin nanofibers were 271,200 and 165,500, respectively.

Electrochromic properties of covalently bonded polyaniline-reduced graphene oxide/single walled carbon nanotubes nanocomposites. A high performance electrochromic material was prepared using polyaniline (PANI) and two different dimensional carbon nanostructures, single-walled carbon nanotubes (SWCNTs) and reduced graphene oxide (rGO) as the components. The covalent bond was introduced to interface between PANI and two carbon nanostructures to form a three-dimensional conductive network. Owing to the high electron conduction through directly connected covalent bond and loose molecular chain aggregation brought by two various dimensional carbon nanostructure, PANI-rGO/SWCNTs nanocomposites exhibit superior electrochemical and electrochromic properties (high optical contrast and short switching time) compared with PANI.

To obtain functionalization of super-engineering plastic, poly(ether ether ketone) (PEEK) substrate, photoinduced self-initiated graft polymerization of several kinds of functional methacrylate was carried out. Graft polymerization proceeded well, and 50–250 nm in thickness graft polymer layers were generated on the PEEK substrate. Surface characteristics such as surface free energy and surface ζ potential on the polymer-grafted PEEK substrate were corresponded to the chemical structure of the graft polymers. Cell attachment on the polymer-grafted PEEK substrate was examined. The surface ζ potentials of the polymer-grafted PEEK substrates governed the cell adhesion density.

The present work focuses on the development of a system enable to modulate, upon an external stimuli, the amount of metal ions uptake. A photoresponsive compound was used as a functional monomer for the preparation, for the first time, of a photoresponsive ion-imprinted polymer (PIIP) for Pd(II) uptake. The photoisomerization capability of the submicroparticles of PIIP, with conformational changes of the polymer, was demonstrated and an improved binding capacity versus Pd(II) was observed after UV exposure of the polymer with maximum binding capacity near to 22 mg g⁻¹.

With the aim of gaining more insight into the heat capacity of amorphous polymers and considering that there are more than a dozen types of data on the absolute value of the heat capacity of polymer compounds, we evaluated the heat capacity of 16 main-chain-type amorphous polymers composed of a carbon backbone using a combination of the Tarasov equation, Einstein equation, and the (C_p − C_V) correction term by taking into account the degree of freedom of monomer units. We found that the heat capacity of the analyzed amorphous polymers could be reproduced using only three fitting parameters from a combination of the Tarasov and Einstein equations below glass transition temperature.

A series of polymeric hemostatic materials are prepared in one-step, by using biobased lactic acid monomers and mature hemostatic drugs (4-aminomethylbenzoic acid or tranexamic acid) through direct melt polycondensation. These materials are powdery with rough and irregular surfaces, and the powder particle size is ~8–30 μm, which is beneficial to the application, immediate hemostasis and scab-bionic membrane forming. Moreover, after the degradation of these materials at 37 °C, more monomers will be released, resulting in a higher efficiency and long-term hemostatic function.

A series of complexes consisting of natural amino acids and tin were developed as a new class of cost-effective catalysts with high reactivity and low toxicity towards some biocompatible aliphatic polyesters. The results demonstrated that Sn(AA)₂ catalysts, especially the phenylalanine-tin complex (Sn(L-Phe)₂) (M_n, up to 194 kg/mol), were suitable for the synthesis of moderate- and high-molecular-weight poly(L-lactide), which exhibited good biocompatibility.

An efficient ambipolar organic transistor (A-OFET) based on the bilayer architecture of p-type poly(benzodithiophene(2-thienyl)-pyrrolopyrrole-dione) (PBDTTPPD) and n-type [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) was demonstrated. The A-OFET exhibits clear bipolar transport and operates as an n-type and a p-type transistor in a single device.

Polylactide (PLA) formed an extended-chain crystal (ECC) and an extended-chain stereocomplex (ECSC) in Langmuir monolayers. Therefore, the chain packings in crystals and SCs could be identified by simply evaluating their sizes. A mixture of a high-molecular-weight (HMW) PDLA and a low-molecular-weight (LMW) PDLA was found to crystallize separately, while a mixture of an HMW-PLLA and an LMW-PDLA was found to form an SC composed of the extended LMW-PDLA chains and the folded HMW-PLLA chains. Furthermore, the molecular structure of SC was successfully visualized at the molecular level by AFM.

The results of this investigation indicate that, compared with the high-molecular-weight amorphous polystyrene, the two low-molecular-weight amorphous polystyrenes studied herein have excess heat capacity below the glass-transition temperature. These results were obtained by analyzing the molecular vibrations of the high-molecular-weight polystyrene. The excitation energy obtained by regression analysis of the excess heat capacity determined by using the Schottky model is consistent with the excitation energy obtained by inelastic neutron scattering. This evidence strongly suggests that the excess heat capacity is due to vibrations of methyl end groups.

Cellulose nanofibers (CNFs) were utilized as nanofillers to improve mechanical properties of polysaccharide composite films made of polyion complexes (PICs) of chondroitin sulfate C (CS) and chitosan (CHI). Nonionic CNFs were homogeneously incorporated in the PIC gels, constructed by multiple electrostatic interactions, and the resulting free-standing films. The filler effects of CNFs were observed, especially in the Young’s modulus of the films in the wet state. Results indicated that CNFs in the films formed a rigid network structure with polysaccharides, contributing the reinforcement of the film strength.

The graphical abstract shows that the kinesin-driven quantum dot transport along microtubule immobilized on a substrate using glutaraldehyde concentration ≤0.10% (v/v) remain unaltered, whereas, at higher glutaraldehyde concentration, >0.10% (v/v), the quantum dot transportation is slowed down.

We evaluated the biocompatibility and biodegradability of implants made of pure PLA and a PLA/PCL blend compatibilized with poly(ɛ-caprolactone-b-tetrahydrofuran) in horses by physical examination, plasma fibrinogen, thermographic, mechanical nociceptive threshold, and ultrasound tests. We also conducted histopathological and surface morphology analyses. Pure PLA and PLA/PCL blends subcutaneously implanted stimulated a minimal inflammatory response and supported cellular infiltration, being biocompatible and biodegradable in horses, with potential for use in equine medicine.

Polypyrrole and poly(N-alkyl pyrrole) grains were synthesized by aqueous chemical oxidative polymerization in the presence of sodium dodecyl sulfate as both a dopant and a hydrophobizing agent. The dried polypyrrole and poly(N-ethyl pyrrole) grains showed hydrophobic character and can act as a light-responsive liquid marble stabilizer. Locomotion of the liquid marble can be driven by near-infrared laser irradiation-induced Marangoni flow on a planar air–water surface. Furthermore, the release of internal liquid can be achieved by controlled disruption of liquid marbles via external stimulus application.

We here demonstrate the importance of ligand–ligand distance on physical property tuning of metallosupramolecular materials by utilizing model-like polyesters bearing pyridine ligands at the side groups with a controlled ligand-distance. The ligand distance is treated as the pyridine group equivalent molecular weight (M_Py) and takes values of 900, 750, 550, and 420. The metal salt ZnCl₂ forms coordination bonds with the pyridine ligands, generating a metallosupramolecular network. DSC and rheological measurements revealed that the glass transition temperatures and apparent activation energy (E_a) of segmental motion changes in a close correlation with 1/M_Py.

TA–Fe@PS-c-PAN NPs were synthesized via a typical FNP procedure. During the process, the water solution containing Fe³⁺ and the organic solution containing polymer and TA diffused into each other under turbulent mixing. As a result, the hydrophobic TA–Fe complex quickly formed and co-assembled into TA–Fe@PS-c-PAN NPs. After carbonization, carbon materials with uniformly dispersed metal NPs were finally and used as effective catalysts for oxygen reduction and evolution reactions.

This article describes the self-assembly of Fmoc-dipeptides comprising α-methyl-L-phenylalanine. The position and number of methyl groups introduced onto the α carbons of the Fmoc-dipeptides as α-methyl-L-phenylalanine have a marked influence on the morphology of supramolecular nanostructures and the hydrogel formation ability.