Mingliang Ma

Fabrication of one-dimensional Fe3O4/P(GMA-DVB) nanochains by magnetic-field-induced precipitation polymerization.

One-dimensional (1D) magnetic Fe(3)O(4)/P(GMA-DVB) peapod-like nanochains have been successfully synthesized by magnetic-field-induced precipitation polymerization using Fe(3)O(4) as building blocks and P(GMA-DVB) as linker. The Fe(3)O(4) microspheres without surface modification can be arranged with the direction of the external magnetic field in a line via the dipolar interaction between Fe(3)O(4) microspheres and linked permanently via P(GMA-DVB) coating during precipitation polymerization. The length of peapod-like nanochains can be controlled by magnetic field intensity, and the thickness of polymer shell can be tuned by the amount of monomers. Magnetic measurement revealed that these 1D peapod-like nanochains showed highly magnetic sensitivity. In the presence of magnetic field, 1D magnetic Fe(3)O(4)/P(GMA-DVB) peapod-like nanochains can be oriented and aligned along the direction of external magnetic field.

Fabrication of 1D Fe3O4/P(NIPAM-MBA) thermosensitive nanochains by magnetic-field-induced precipitation polymerization

One-dimensional (ID) magnetic thermosensitive Fe3O4/poly(N-isopropylacrylamide–N,N′-methylenebisacrylamide) (P(NIPAM-MBA)) peapod-like nanochains have been successfully synthesized by magnetic-field-induced precipitation polymerization using Fe3O4 as building blocks and P(NIPAM-MBA) as linker. Fe3O4 microspheres can be arranged with the direction of an external magnetic field in a line via the dipolar interaction between Fe3O4 microspheres and linked permanently via P(NIPAM-MBA) coating during precipitation polymerization. 1D magnetic Fe3O4/P(NIPAM-MBA) peapod-like nanochains can be oriented and aligned along the direction of the external magnetic field. More interestingly, Fe3O4 microspheres in each peapod were regularly arranged in a line and periodically separated through the P(NIPAM-MBA) layers with a visible interparticle spacing.

Fabrication and characterization of 1 D Fe3O4/P(NIPAM–MAA–MBA) nanochains with thermo- and pH-responsive shell for controlled release for phenolphthalein

One-dimensional (1D) Fe3O4/poly(N-isopropylacrylamide-methacrylic acid-N,N′ -methylenebisacrylamide)(Fe3O4/P(NIPAM–MAA–MBA)) peapod-like nanochains have been successfully synthesized by magnetic field-induced precipitation polymerization. Fe3O4 microspheres modified with vinyl groups can be arranged with the direction of the external magnetic field in a line and linked permanently via P(NIPAM–MAA–MBA) coating during precipitation polymerization. The properties of 1D Fe3O4/P(NIPAM–MAA–MBA) were characterized by transmission electron microscopy, X-ray diffraction, thermogravimetric analysis (TGA), vibrating sample magnetometry, X-ray photoelectron spectroscopy, and UV–Vis spectrophotometer. Magnetic measurement revealed that these 1D peapod-like nanochains showed highly magnetic sensitivity. The thermal- and pH- response of 1D magnetic Fe3O4/P(NIPAM–MAA–MBA) nanochains was investigated by the temperature/pH dependence of hydrodynamic radius of Fe3O4/P(NIPAM–MAA–MBA) microspheres. The release behavior of phenolphthalein from 1D magnetic Fe3O4/P(NIPAM–MAA–MBA) nanochains could be effectively controlled by changing the temperature/pH values.

Three new conjugated polymers based on benzo[2,1-b:3,4-b′]dithiophene: synthesis, characterization, photoinduced charge transfer and theoretical calculation studies

Three new conjugated polymers have been designed and synthesized via the alternate copolymerization of the electron-donating monomer benzodithiophene (BDT) and three different electron-accepting monomers: 5,8-dibromoquinoxaline, 5,8-dibromo-2,3-diphenylquinoxaline, 10,13-dibromodibenzo[a,c]phenazine. The synthesized polymers show good solubility in common organic solvents as well as broader absorptions in the visible region and narrower optical band gaps compared to homopolymers made from BDT units. It is found that the absorptions of the copolymers are red-shifted by increasing the electron-withdrawing ability of the co-monomer. In particular, the absorption edge of the P3 film extends to 778 nm, whereas that of the P1 film is only at 636 nm. Theoretical calculation studies of structure–property relations indicated that polymer chains with better coplanarity or π–π* delocalization will lead to lower band gaps. Photoinduced charge transfer (PCT) studies disclosed that exciton dissociation of photoexcited PX (X = 1, 2, 3) via electron-transfer may occur at the interface with CHL-C60, enabling the photogeneration of electrons and holes. The P3/CHL-C60 blended film was chosen as a representative sample to test the applicability of the polymer P3 for energy conversion, a 1.76% PCE was finally obtained.

Evaluation of thiol-ene photo-curable resins using in rapid prototyping

Purpose The purpose of this paper is to evaluate the properties of several thiol-acrylate photosensitive systems and compare with corresponding acrylate free-radical systems. The potential stereolithography applications of thiol–ene photosensitive systems are also discussed. Design/methodology/approach In the both thiol–ene and acrylate free-radical photosensitive systems, various key performances were characterized. The function group conversions were characterized by real-time Fourier transform infrared spectroscopy. The tension strength was determined according to the standard ASTM D638-2003, the flexible strength was determined according to ASTM D790-07 and the hardness was measured according to ASTM D2240-05. The volume shrinkage was measured by dilatometer method. The glass transition temperature was analyzed by differential scanning calorimeter. Findings As adding mercapto propionates into acrylate system, the inhibition of polymerization by oxygen was controlled and the flexible performance was improved. In addition, the photosensitive resin showed better tension strength, higher elongation at break and lower volume shrinkage. Among the four mercapto propionates, rigid TEMPIC showed most obvious affect, followed hexa-functional DPMP, tetra-functional PETMP and tri-functional TMMP. Originality/value Although the thiol–ene photosensitive resin has unmatched advantages in performance, there are no reports on the thiol–ene photosensitive resin in the stereolithography application. In this study, thiol–ene photopolymerization material was first tentatively implemented in stereolithography area. Several critical performance parameters were compared between thiol–ene and acrylate free-radical photosensitive systems.

Preparation of Monodisperse Large-Size Cross-Linked P (GMA-St-EGDMA) Microspheres by Two-Step Swelling Polymerization

Monodisperse large-size cross-linked P(GMA-St-EGDMA) microspheres were prepared by two-step swelling polymerization, P(GMA-St) microspheres as seeds. Effects of swelling conditions such as the kind and amount of swelling activation agent, temperature and EGDMA on the size and size distribution of the P(GMA-St-EGDMA) microspheres were investigated in detail. The morphology and properties were analyzed by optical microscopy, SEM and TGA. The results showed that monodisperse cross-linked P(GMA-St-EGDMA) micropheres with 14 μm could be successfully prepared.

Synthesis and Formation Mechanism of Large-Size Monodisperse P(Glycidyl methacrylate-Styrene) Microspheres by Batch Dispersion Copolymerization

Highly monodisperse P(Glycidyl methacrylate-Styrene) (P(GMA-St)) microspheres with spherical shape and smooth surface were prepared via batch dispersion copolymerization of GMA and St in ethanol medium, using 2,2′-azobisisobutyronitrile (AIBN) as initiator and polyvinylpyrrolidone (PVP) as stabilizer, respectively. The effects of various polymerization parameters such as St/GMA ratio and total monomer concentration on the morphology, particle size and size distribution were investigated. It was found that P(GMA-St) microspheres could be obtained with a size range of 2 to 9 µm by changing the solubility parameter of reaction mixture. St/GMA ratio had an important effect on the particle size and size distribution, and increasing the relative percentage of styrene in the mixture lead to an increase in particle size and a decrease in the molecular weight of copolymer when the St/GMA ratio was not more than 1. Monodisperse microspheres were obtained when the total monomers loading ranged from 10 to 25 wt%. Inner structure was observed by optical microscopy and a reasonable formation mechanism of P(GMA-St) was proposed.