Research articles

We report a facile method for synthesizing Au NPs based on alkali/urea regenerated cellulose hydrogels. By controlling the precursor concentration and the reaction temperature, the size of the Au NPs can be adjusted. The Au NP/cellulose hydrogels can be used as efficient heterogeneous catalysts in the reduction of 4-nitrophenol.

A versatile and simple strategy for building self-healing hydrogels with tunable mechanical properties and shape memory behavior has been developed using diethylenetriamine to crosslink polyacrylic acid chains. Hydrophobic domains form in the network in addition to ionic bonds between the amino and carboxylic acid groups. The combination of ionic bonds and hydrophobic interactions not only provides self-healing ability but also drastically improves the strength.

6 groups of blend membranes based on carboxymethyl chitosan (CMCTS) or carboxymethyl chitin (CMCT) were prepared. CMCTS-Gel (1#) and CMCT-Gel (4#) blend membranes with high transmittance and surface properties were more suitable for cell growth. Although primary corneal epithelial cells (CECs) on the two blend membranes could keep marker proteins and prevent cell fibrosis, CECs on membrane 4# could maintain the original epithelial morphology and improve the K12 protein level seriously. The potential mechanism of anti-fibrosis effect was proved that both of the membranes could block phosphorylation levels of Smad2 and Smad3, and membrane 4# could also depress the total native Smad2 and Smad3 expressions.

Photoinduced molecular switches were achieved by atropisomeric polymers containing conjugated structures of azo and binaphthyl units. trans-cis Photoisomerization of the azo unit led to molecular twisting motion of the binaphthyl unit, yielding chiroptical switching in a neat film. The atropisomeric polymers also displayed photoswitchable fluorescence by repeated irradiation of UV and visible light. Irradiation of the neat film with linearly polarized light caused selective excitation of the atropisomeric polymer, leading to anisotropic molecular orientation.

We synthesized side-chain crystalline block copolymer that exhibit an adsorptive interaction with polyethylene (PE) using a monomer with a long alkane side chain and a hydrophilic monomer. By coating PE with a dilute solution of these block copolymers, the PE surface can easily be endowed with hydrophilicity in a uniform manner. This method does not require a special experimental apparatus or reagents and is more viable than conventional methods in terms of energy efficiency and cost, which means it has a lower environmental impact. Based on the measured contact angle on the modified PE surface, we also evaluated the effects of copolymer concentration in the coating solution and the degree of polymerization in the functional region of the copolymer. The results suggest that the hydrophilicity of the PE surface can be controlled by adjusting these parameters.

Novel high-refractive-index materials consisting of poly(thiophosphonate)s were developed by the polycondensation of phenylthiophosphonic dichloride with various bisphenols. These polymers exhibit excellent thermal stability (T_d5 > 420 °C), moderate to high glass transition temperatures (117–204 °C) and high transparency in the visible light region. Furthermore, they achieve high refractive indices of 1.626–1.687 owing to the highly polarizable sulfur and phosphorous atoms in their backbones and relatively high Abbe numbers of 21.3–27.5.

The introduction of structural defects into ordered mesoporous carbons is demonstrated based on block copolymer-templating and high-temperature carbonization of N-containing polymers. N-atom removal during high-temperature heat treatment induces structural defect formation, and the use of soft-templating yields dense mesostructures tough enough to maintain ordering upon defect introduction.Please change the graphical abstract to the revised one sent by email separately.

This study demonstrated convenient preparation methods for the introduction of cationic and cross-linkable moieties into 2-branched and 4-branched PCL and their corresponding stable materials. The cationic content and the ratio of 2-branched and 4-branched monomers could be simultaneously controlled by incorporating non-cationic macromonomers. Zeta potential measurements proved that the cationic charge could be controlled by changing the temperatures. Human MSC adhesion was observed on the PCL materials with different cationic contents and lower contents of cationic contents seem to be preferable. Consequently, such materials are promising for biomaterials research.

The influence of poly(butylene succinate) (PBS) crystals on the crystallinity of poly(ethylene oxide) (PEO) in PBS/PEO blends, which exhibit interpenetrating spherulites, was examined. The degree of crystallinity, ϕ, of each component was obtained by pulsed nuclear magnetic resonance (NMR). The dilution effect, order of crystallization, and change in the glass transition temperature upon blending were discussed as factors contributing to the ϕ. PEO exhibited an apparent secondary crystallization, where ϕ gradually increased and the mobility of the chain segments was suppressed. The secondary process of PBS was nearly negligible.

MMA-BnMA copolymers with various monomer sequences (blocky, random, alternating tendency) were prepared by partial modifications of atactic poly(BnMA) or by direct copolymerization of MMA and BnMA. ¹³C NMR spectra of the copolymers were subjected to principal component analysis, one of the standard procedures of multivariate analysis. The analysis showed clearly the formation of highly blocky copolymers by hydrogenolysis as well as the formation of copolymers with somewhat alternating tendency by the acidic debenzylation, saponification, and transesterification at late processes of the reactions.

Water-in-oil (W/O) gel-emulsions consisting of water and a monomer were successfully prepared using N-3-hydroxypropylcarbonyl-L-isoleucyl-aminooctadecane as a gelator. Low-temperature polymerization of the gel-emulsions with a redox initiator was performed to obtain the corresponding porous polymers. Polymerization of gel-emulsions containing bifunctional monomers gave crosslinked porous polymers, which were found to be mechanically robust and solvent resistant. The adsorption capacities of the polymers toward several liquids were assessed and rationalized in terms of the surface microstructures of the polymers. The time courses of the adsorptions were investigated, revealing a two-step adsorption process comprising rapid permeation into the cavities of the porous polymers followed by a slow swelling step.

Random copolymers (P(M_100-m/T _m )) composed of 2-methacryloyloxyethyl phosphorylcholine, which suppresses protein fouling, and 3-(triethoxysilyl)propyl methacrylate, which can react covalently to the glass surface, were prepared via photoinitiated radical polymerization. Coating of the glass with P(M_100-m/T _m ) was confirmed by red fluorescence from Rhodamine 6G. The protein antifouling properties of the P(M_100-m/T _m ) coating on glass were confirmed using fluorescence-labeled proteins.

The origin of the reaction rate acceleration in the microwave-assisted synthesis of poly(butylene succinate) (PBS) was investigated by measuring the rate of removal of the water by-product from the reaction solution under equivalent reaction conditions using both microwave and conventional heating methods. Microwave heating selectively activated and removed the water from the reaction solution more rapidly and to a greater extent than oil bath heating. These results indicate that the principal effect of microwave irradiation in the synthesis of PBS was the accelerated removal of the water by-product.

The interphase structure of isotactic poly(methyl methacrylate) (it-PMMA)/aluminananoparticle mixtures obtained from tetrahydrofuran (THF) solution was discussed. The it-PMMA in the mixtures forms two amorphous phases (crystallizable and incrystallizable phases) depending on casting conditions from THF. The polymer interphase on Al2O3 particles changes into a crystallizable structure with a trans-gauche rich conformation and amorphous. The interphase shows a lower Tg than the melt-cast one and is easy to crystallize at low temperature. The novel structure was formed by the conformation freezing of the polymer at Al2O3 surface.

Amphiphilic incompletely condensed polyhedral oligomeric silsesquioxanes possessing various substituents and poly(ethylene glycol)s of different chain lengths have been developed. It has been elucidated that their self-association behaviors in water are dependent on the substituents and chain lengths of poly(ethylene glycol)s. Precise molecular design, excellent thermal stability, and good dispersibility have been realized at once.

Polydiacetylene (PDA) derivatives exhibit color change with application of external stimuli, such as heating and mechanical stress. The original layered PDA shows the irreversible color transition from blue to red with heating at the threshold temperature. Here we found that the alkyldiamine-intercalated PDA induced the different color-change properties, such as the raise of the color-transition temperature, the temperature-dependent color-change, and the reversible color change. The intercalated diamines have the stabilization effect of the layered polymer. The stimuli-responsive color-change properties can be tuned by the intercalated organic guests.

Reverse osmosis membranes have been playing a main role for the desalination of water in the world. Hydration structure of polyamide functional layer of the membrane was studied via neutron scattering and atomistic molecular dynamics simulations. Experimental and computational structure factors, S(Q), of the polyamide/water system showed good agreement. Water clusters in water-rich system were well connected to each other and formed channel-like structure. Polyamide–water interactions and polyamide-polyamide interactions, which are thought to be important to enhance the performance of the membranes, were examined in detail.

Molecularly imprinted hydrogel layer SPR sensor chips with lectin-recognition sites, which were prepared via surface-initiated atom transfer radical polymerization (SI-ATRP) combined with molecular imprinting, exhibited not only large SPR signal change in response to a target lectin but also inhibited nonspecific protein adsorption.

The effects of long-term storage of poly(3-hydroxbutyrate-co-3-hydroxyvalerate) were evaluated over a range of temperatures. As the storage temperatures were increased towards 100 °C, secondary crystallisation resulted increasing the melting point, Tg, modulus and strength. At 125 and 150 °C secondary crystallisation and degradation occurred simultaneously; the effects of degradation masked by secondary crystallisation. The significant observation is that the degradation process remains active at storage temperatures well below the melting point and long-term stability of P(3HB-co-3HV) is not only affected by secondary crystallisation, but also sub-melting point degradation.

The alternating conjugated polymer was synthesized with thiophene-substituted aza-boron dipyrromethene. The synthesized polymer had the near-infrared light-absorbing ability (molar extinct coefficient: 48,000 M⁻¹cm⁻¹) in the region over 1300 nm with the peak at 864 nm. From the electrochemical data, it was found that the polymer had the deep lowest unoccupied molecular orbital (LUMO) level. This result means that only the highest occupied molecular orbital level was influenced and the LUMO can be preserved by extension of π-conjugation through the polymer main-chain.