Designed Monomers and Polymers最新文献

Electrospinning provides a versatile, efficient and low-cost method for the preparation of continuous nanofibres from various polymers. In this study, the polyhedral oligomeric silsesquioxanes (POSS) block copolymer was synthesized via atom transfer radical polymerization. The smooth fiber, porous fiber or hierarchically porous microspheres were prepared by electrospinning from POSS block copolymer, poly(vinylidene fluoride) (PVDF) and aluminium oxide (Al₂O₃). The influence of copolymer concentration, the ratio of the solvents, the diameter and concentration of the Al₂O₃ on the surface morphology were investigated. Porous fibers and porous microspheres were prepared by regulating the ratio of the solvents from the phase separation and breath figure methods. The dynamic behavior of the water droplet with the constant volume impacting on the electrospinning films were reported. The morphology evolution, restitution coefficient, the change of energy of the water droplets are examined. The droplet bounces several times on the superhydrophobic surface, while the droplet remains pinned and does not rebound when the contact angles was lower than 150°. On the other hand, the water droplets were splashed on the Al₂O₃ based electrospinning films. Finally, the mechanical properties of the electrospinning films were investigated.

Magnetic nanoparticles (MNPs) with safety, stability and excellent magneto-calorific effect are the precondition for the smart magnetic drug carriers' fabrication and controllable drug release at a specific target in clinical treatment. In this study, the drug release and magneto-calorific effect of two types of magnetic lipid microcapsules (MLMs) loading lipid-coated MNPs and uncoated MNPs respectively were compared deeply in experimental analysis and theoretical simulation. The simulation results revealed that almost same magnetic heat effect and temperature increasing exist between lipid-coated and uncoated MNPs, which was consistent with the experimental drug release results. Coating lipid on MNPs didn't affect the magnetic heat and heat transfer of the MNPs. Because of the heat transfer between MNPs and water, MLMs and water around, the temperature increasing of whole sample solution is lower than that of the MNPs themselves. Our results provide a reliable theoretical basis for the development of healthy, safe, and biocompatible drug delivery systems.

A Cu(II) coordination polymer with the composition of [Cu₂(L)₂(4,4'-bipy)₂]_n·2 n(ClO₄) (1, HL = 4-methyl-L-phenylalanine and 4,4'-bipy is 4,4'-bipyridine), was successfully obtained by the reaction of the mixed ligand of HL and 4,4'-bipy with Cu(ClO₄)₂ · 6H₂O under solvothermal condition. The as-synthesized compound not only has high thermal stability until 275°C but also excellent photocatalytic activity for the methyl blue solution degradation under the irradiation of ultraviolet light. Furthermore, the compound's treatment activity on the diabetes was determined and its relevant mechanism was also studied. The cytotoxicity or hemolysis toxicity (HC50) of the synthesized compound was also evaluated in this research.

A new type of superhydrophobic borneol-based polymeric coating has been prepared. The chemical composition of the polymer particles was analyzed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, which showed that the polymer did not contain fluorine, which can effectively avoid the cytotoxic risk of fluorine. By dynamic light scattering, scanning electron microscopy, and static contact angle measurement, the contact angle of the prepared coating gradually increased with increasing diameter of the polymer particles, and a superhydrophobic coating surface was finally obtained. Interestingly, after dissolving the superhydrophobic sample with tetrahydrofuran and making it a normal hydrophobic sample, the antiadhesion performance for E. coli was greatly reduced, and it could not effectively prevent E. coli adhesion. In addition, a long-term antiadhesion study of bacteria was performed. The superhydrophobic borneol-based polymer coating showed long-term resistance to E. coli adhesion. Therefore, the excellent antibacterial properties and cell compatibility mean that this series of polymer materials has great potential in the field of biomedicine.

Endeavors have been made to construct new donor-acceptor (D-A) monomers utilizing 9 H-carbazole (CB) as electron donors and different electron acceptors. All estimations were finished using DFT and TD-DFT, and B3LYP level with a 6-311 G basis set in the gas and chloroform solvent. The impacts of the distinctive acceptors on the geometry of molecules and optoelectronic properties of these D-A monomers were discussed to dissect the connection connecting the molecular structures and the optoelectronic properties. Likewise, the HOMO - LUMO energies, atomic orbital densities are calculated theoretically. Notwithstanding the charge transfer measure between the carbazole electron donor unit and the electron acceptor one is upheld by breaking down the optical spectra of the acquired monomers and the restriction of involved HOMO and LUMO. The outcomes show that the D-A monomers, CB-ODP, CB-TDP, and CB-SDP, are acceptable for optoelectronic applications in organic solar cells like BHJ.

Implanted medical devices that have poor friction property or biofilm formation can limit their service life and cause discomfort in patients. Recently, some zwitterionic coatings have been studied to modify the biomaterials surface for lubricating function, but the grafting methods of coatings are complicated and also seldom take the bacterial antiadhesion property into account at the same time. In our studies, motivated by the properties of nature mussels and human articular, we firstly successfully synthesized double adhesion protection of self-adhesive ternary polymer coating and achieved the excellent lubrication and antifouling functionalization of the medical devices surface. In details, the X-ray photoelectron spectroscopy, scanning electron microscope and the water contact angles could characterize the successful modification on the surface of titanium substrate. Additionally, the tribological tests carried out by atomic force microscope verified the ternary polymer could enhance the lubrication property owing to the hydration lubrication mechanism. Meanwhile, it also possessed the bacterial antiadhesion property for the initial 24 h attributed to the hydration repulsive force. We believe that, as a simple and universal preparation method, the ternary polymer could make a great significance for improving the surface function of biomaterials and alleviating patients' discomfort.

Novel monomer, N, N'-bis(acryloyl) cystinamide (NBACA), was designed and synthesized with L-cystine as row material. By using this NBACA both as the monomer and crosslinker, reduction-sensitive nanohydrogel was prepared in ethanol via distillation-precipitation polymerization. The obtained nanohydrogel can provide a relatively hydrophobic environment and hydrogen-bonding sites inside the gel; therefore, it is suitable for loading hydrophobic drug. When paclitaxel that possess poor water-solubility was used as a model drug, the nanohydrogel represented a high drug-loading capacity, and dispersed well in aqueous solutions. Furthermore, the disulfide-group-containing nanohydrogel exhibited good reduction-sensitive drug-release behavior. The nanohydrogel biodegraded rapidly in a reducing environment, and released approximately 80% of the PTX within 24 h. Cytotoxicity assays showed that the PTX-loaded nanohydrogel exhibited high cytotoxicity against MCF-7 breast cancer cells, while blank nanohydrogels displayed a negligible cytotoxicity.

The kinetics of ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) initiated by 1.0, 1.5 and 2.0 mol% of stannous(II) octoate/n-hexanol (Sn(Oct)₂/n-HexOH) wase successfully studied by non-isothermal differential scanning calorimetry (DSC) at heating rates of 5, 10, 15 and 20 °C/min. The DSC polymerization kinetic parameters of ε-CL were calculated using differential (Friedman) and integral isoconversional methods (Kissinger-Akahira-Sunose, KAS). The average activation energy (E_a ) values obtained from Friedman and KAS methods were in the range of 64.9-70.5 kJ/mol and 64.9-80.4 kJ/mol, respectively. The values of frequency factor (A) were determined from model fitting method using Avrami-Erofeev reaction model. The average values of A for the ROP of ε-CL initiated by 1.0, 1.5 and 2.0 mol% of Sn(Oct)₂/n-HexOH (1:2) were 7.3x10⁷, 2.8x10⁶ and 1.2x10⁶ min^-1, respectively. From kinetics studied, the polymerization rate of ε-CL increased with increasing initiator concentration. The performance of Sn(Oct)₂/n-HexOH in the synthesis of poly(ε-caprolactone) (PCL) was investigated by bulk polymerization at temperatures of 140, 160 and 180 °C. Sn(Oct)₂/n-HexOH (1:2) could produce high number average molecular weight ( $\overline{M_n}$ = 9.0 × 10⁴ g/mol) and %yield (89%) of PCL in a short period of time at Sn(Oct)₂ concentration of 0.1 mol% and temperature of 160°C. The mechanism of the ROP of ε-CL with Sn(Oct)₂/n-HexOH was proposed through the coordination-insertion mechanism.

The research on the diffusion of water in coatings has been a hot topic in many fields, such as chemistry, coating structure and hydrogen bonding. In this paper, DGEBA epoxy coating was used as a sample to explore the diffusion process of 3 wt.% NaCl solution at different temperatures. Two-stage diffusion was established by immersion experiment and MD simulation. The synergistic effect of temperature and water on DGEBA properties was revealed by FTIR method and adsorption-desorption cyclic testing. The results showed that as the temperature increased, the saturation water content in coatings increased. At different temperatures, the diffusion process of water presented two-phase characteristics, and the influence of temperature on the diffusion process was mainly manifested in the cross-linking density at higher locations. Based on the variation law of swelling coefficient in per unit time (24 h), the conditions for water-coating interaction and formation of water clusters in this paper were proposed. The synergistic effect of water and temperature on DGEBA properties was reflected in two aspects: at lower temperature (20 °C), water would only change the physical structure of the coatings, while the water broke the DGEBA chains at higher temperature (60 °C).

At present, bacteria continue to threaten human health, and the resistance of bacteria to antibiotics continues to increase, so the development of new antibacterial agents and antibacterial materials is increasingly important to ensure human health. In this paper, three polyether biguanide compounds with high antibacterial properties were synthesized by reacting polyetheramine T403 with o-tolylbiguanide, m-tolylbiguanide and p-tolylbiguanide (o-TTB, m-TTB and p-TTB), respectively. The antimicrobial performance of polyether biguanide against E. coli and S. aureus was evaluated using a minimum inhibitory concentration method, and the results showed that the synthesized polyether biguanide exhibited efficient and broad-spectrum antimicrobial effects. Among them, o-tolyl biguanide derivative o-TTB showed the best antimicrobial performance, with minimum inhibitory concentrations of 20 and 15 μg/mL against E. coli and S. aureus, respectively. Then, epoxy resin E51 was cured using the obtained TTB as a curing agent to prepare an epoxy resin with antibacterial properties. The inhibition of the growth of S. aureus by the cured o-TTB/E51 resin was investigated by incubating the cured epoxy resin with bacteria, and the results showed that the cured resin had a significant inhibitory effect on the growth of bacteria. The non-isothermal curing kinetics of the o-TTB/E51 system were investigated by differential scanning calorimetry (DSC) to determine the optimized curing reaction temperature, curing kinetic parameters and curing kinetics equation.