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Metal–organic frameworks (MOFs) have received great attention in environmental remediation application. In particular, one-dimensional (1D) MOF materials have excellent catalytic degradation perfor...

A series of β-Bi2O3/BiOBr heterojunction photocatalysts were successfully synthesized by in-situ treatment of β-Bi2O3 with HBr. The as-synthesized β-Bi2O3/BiOBr composites displayed remarkably enhanced visible light photocatalytic activity for RhB degradation compared to pure β-Bi2O3 and BiOBr. The value of the apparent rate constant for the optimal sample was about 50.9 and 7.1 times higher than that of pure β-Bi2O3 and BiOBr, respectively. The enhanced photocatalytic activity is attributed to the formation of a heterojunction between β-Bi2O3 and BiOBr, which leads to an efficient separation of electron-hole pairs. The present work provides a new type of visible-light-active β-Bi2O3-based heterojunction photocatalysts that are promising for practical applications.

A series of β-Bi2O3/BiOCl heterojunction photocatalysts were successfully synthesized by in-situ treatment of β-Bi2O3 with HCl. Compared to pure β-Bi2O3, the as-synthesized β-Bi2O3/BiOCl composites displayed unexpectedly high visible-light photocatalytic activity for RhB degradation, which was even higher than that of P25 under UV light. Based on the results of transient photocurrent measurement and trapping experiments of active species, the enhanced photocatalytic activity could be ascribed to the formation of heterostructure between β-Bi2O3 and BiOCl, leading to the efficient separation of electron-hole pairs. This research may establish foundation for practical application of the new visible–light–active β-Bi2O3-based heterojunction photocatalysts.

An N-doped TiO2/MoS2 heterojunction photocatalyst constructed by two-dimension MoS2 nanosheets and N-doped TiO2 nanoparticles was successfully synthesized by a hydrothermal method. The synthesized N-TiO2/MoS2 composites were characterized by XRD, XPS, TEM, UV–vis DRS and PL, and its visible photocatalytic activity was evaluated by degradation of methylene blue. The results showed that N-doped TiO2/MoS2 heterojunction photocatalyst achieved more enhanced photocatalytic activity compared with pure TiO2, MoS2 and N-doped TiO2 for degradation of MB. Trapping tests with different scavengers indicated that not hydroxyl radicals ( OH) but superoxide radicals ( O2−) and photogenerated holes (h+) were highly responsible for the degradation process. The reusable experiments showed that the prepared N-doped TiO2/MoS2 heterojunction photocatalyst was stable during the photodegradation of MB and will have practical applications for environmental remediation.

Tungsten oxide (WO3) nanoplate films with a relatively rough surface were successfully fabricated via a simple hydrothermal method, followed by the hybrid microwave annealing (HMA) treatment only a few minutes for the first time. The microscopic morphology and phase were characterized by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM), Raman spectrum and X-ray diffraction (XRD). Photoelectrochemical measurements demonstrated that the obtained WO3 film of microwave processing for 11 min exhibited the photocurrent density of 1.60 mA/cm2 at 1.2 V (vs. Ag/AgCl) and the IPCE value of 55% at 355 nm under an applied voltage of 1.0 V (vs. Ag/AgCl), which were about 3 and 2.5 times compared with the WO3 film prepared by the conventional annealing method, respectively. Moreover, the WO3-HMA films were applied to the versatile photoanode-driven photoelectrochemical system for CO2 reduction into formic acid. The maximum formic acid generation rate and faradaic efficiency of the WO3-HMA films were 9.21 μmol h−1 cm−2 and 45.45%, respectively. This study provided a facial and rapid method to synthesize the high-performance WO3 photoanodes with better photoelectrochemical and photoelectrocatalytic activities.

N-doped TiO2 nanoparticles deposited on reduced graphene oxide sheets were successfully prepared by a photoreduction method. The synthesized N-TiO2/rGO composite was characterized by XRD, SERS, XPS, TEM, UV–vis DRS and PL, and its visible-light photocatalytic activity was evaluated by degradation of tetracycline hydrochloride (TC). The results showed that N-TiO2/rGO composites exhibited a more enhanced photodegradation activity compared to pure TiO2 and N-doped TiO2. Trapping tests indicated that not OH and h+ but O2− was chiefly responsible for the photodegradation process. The reusable experiments showed that the prepared N-TiO2/rGO catalyst was stable during the photodegradation of TC.

A novel heat-curable silicone rubber (MCSR/Si-PAMAM) was prepared by using siloxane polyamidoamine (Si-PAMAM) dendrimers as cross-linkers and polysiloxane containing γ-chloropropyl groups as gums. The chemical cross-linking occurs through the reaction between Si-PAMAM dendrimers and polysiloxane containing γ-chloropropyl groups. The effect of various amounts of cross-linkers on mechanical properties of MCSR/Si-PAMAM was discussed in this paper. MCSR/Si-PAMAM exhibits favorable mechanical properties with a tensile strength of 10.06 MPa and a tear strength of 47.9 kN/m when the molar ratio r of [N-H]/[CH2CH2CH2Cl] is 1:1. These excellent mechanical properties can be attributed to the formation of concentrative cross-linking from Si-PAMAM dendrimers in the cross-linking networks, along with the introduction of Si–O–Si units in the internal structure of dendrimers. The introduction of Si–O–Si units reduces the steric hindrance of molecular structure, which facilitates the N–H bonds in the interior layers of dendrimers to react with γ-chloropropyl groups. In addition, thermogravimetric analysis results indicate that MCSR/Si-PAMAM is thermally stable even at high temperatures in a nitrogen atmosphere. Differential scanning calorimetry analysis reveals that the glass transition peak of MCSR/Si-PAMAM is not identified in the temperature range −150 to −30°C, only a melting endothermic peak at −40°C.

BiVO4/WO3 heterojunction film is considered as a very promising candidate for photoelectrochemical water splitting. However, the BiVO4/WO3 films prepared by a conventional method exhibit numerous grain boundaries in the BiVO4 layer and a weak contact at the heterojunction interface. In this paper, we found that BiVO4 could be formed from hydrothermal Bi2WO6 in the weak acid solution dissolving V2O5 and successfully developed an in situ transformation method to prepare BiVO4/WO3 heterojunction films. The prepared BiVO4/WO3 heterojunction films were characterized in detail and showed a high quality core/shell WO3/BiVO4 structure. The formation mechanism of the BiVO4 layer on the surface of WO3 film has been put forward. In particular, the prepared BiVO4/WO3 films were used as photoanodes and showed an excellent visible light response, a good photostability and high photoelectrochemical activity. The photocurrent density for BiVO4/WO3 photoanode was up to 2.92 mA cm−2 at 1.81 VRHE without additional electrocatalyst or doping under visible light illumination.

A much simpler and broadly applicable dip-coating method using silica nanoparticles and a silane coupler for preparing hydrophobic paper is presented. Both producing surface hydrophobization without additional surface treatment and increasing the adhesive force between the paper and the coated material can be realized by an almost one-step procedure. The modified filter paper could not only selectively permeate oil from a mixture, but also exhibits superior recyclability, indicating its great potential application in the oil–water separation area.

From the point view of molecular structure design, three different kinds of amphoteric polycarboxylate superplasticizers (APC) by introducing a cationic monomer such as [2-(methacryloyloxy)ethyl]trimethylammonium chloride (DMC), 3-[2-(methacryloyloxy)ethyl]dimethylammonio-propane-1-sulfonate (DMAPS) and acrylamide (AM) were synthesized by free radical polymerization. The functional groups, molecular weights and molecular weight distributions of these superplasticziers were characterized by Fourier transform infrared spectra (FT-IR) and gel permeation chromatography (GPC). The dispersion performance of as-prepared APC were evaluated by the fluidity of cement paste and cement mortar. The results showed that the fluidities of samples mixed with APC were higher than that of the conventional polycarboxylate ether (PCE) superplasticizers, indicating excellent dispersion performance and dispersion retention. The strengths of concrete with APC or PCE were greatly improved compared with that of the standard concrete, and the strengths of samples with APC were superior to that with PCE. By substituting cement with 1 wt% sodium bentonite, the fluidity of the cement pastes with APC was higher than that with PCE1, which can be ascribed to the enhanced clay tolerance of APC. Total organic carbon (TOC), X-ray diffraction (XRD) and thermo gravimetric analysis (TGA) were conducted to study the adaptability of superplasticizers to cement and clay. Adsorption capacity measurement revealed that APC and PCE exhibit selective adsorption on cement and clay and APC exhibited better adaptability to clay than PCE. The interlayer spacing of sodium bentonite increased by 0.2 nm after the adsorption of superplasticizer, without significant difference between APC and PCE. A possible mechanism was proposed that the cationic groups can insert into the interlayer of clay by cation exchange, and the intercalation of PEO side chains was inhibited, which is different from that of PCE.

Solvent and coating mode play crucial roles on the formation of polymeric surface patterns. Investigation by AFM revealed that a ternary hydrophilic–lipophilic–fluorophilic block copolymer can self...

Triple stimuli (temperature/pH/photo)-responsive amphiphilic glycopolymer, poly(2-(dimethylamino)ethyl methacrylate-co-6-O-methacryloyl-1,2,3,4-di-O-isopropylidene-D-galactopyranose)-b-poly(4-(4-methoxyphenylazo)phenoxy methacrylate) [P(DMAEMA-co-MAIpGP)-b-PMAZO] was synthesized by atom transfer radical polymerization, followed by the hydrolysis of MAIpGP groups, resulting in the target product poly(2-(dimethylamino)ethyl methacrylate-co-6-O-methacryloyl-D-galactopyranose)-b-poly(4-(4-methoxyphenylazo)phenoxy methacrylate) [P(DMAEMA-co-MAGP)-b-PMAZO]. The composition, moleculer weight, and moleculer weight distribution of the resultant polymers were characterized by 1H NMR and gel permeation chromatography. The micelles formed in aqueous solutions were simulated by various chemical and physical stimuli and characterized by dynamic light scattering, transmission electron microscopy, and UV-vis spectroscopy. It was found that the glycopolymer is responsive to three different types of stimulus (light, temperature, and pH). The poly(2-(dimethylamino) ethyl methacrylate) segments give thermo- and pH-responsiveness. The presence of the azobenzene moiety endows the block copolymer to exhibit light-responsiveness due to its reversible trans-cis isomerization conversion. The triple stimuli-responsive glycopolymer micelles can simulate biomacromolecues in vivo/in vitro environment and can be expected to open up new applications in various fields. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2131–2138

Well-defined amphiphilic triblock copolymers PMAGP-b-PLA-b-PMAGP with varied compositions and molecular weights were obtained via a four-step procedure. The hydrophilicity and water absorption increase with an increase of the PMAGP chain length. The presence of active hydroxyl groups was confirmed by a dyeing procedure.

Novel thermo-sensitive zwitterionic ABC-type triblock copolymers poly(ethylene glycol)-block-[2-(methacryloyloxy)ethyl]dimethyl(3-sulfopropyl)-ammonium hydroxide-block-poly[2-(dimethylamino)ethyl methacrylate] (MPEG-b-PSBMA-b-PDMAEMA) were synthesized by atom transfer radical polymerization (ATRP). The bromide-terminated diblock copolymers poly(ethylene oxide)-block-[2-(methacryloyloxy)ethyl]dimethyl(3-sulfopropyl)-ammonium hydroxide (MPEG-b-PSBMA-Br) were prepared by the ATRP of methacryloxyethyl sulfobetaine initiated by the macroinitiator MPEG-Br, which was obtained by the esterification of poly(ethylene glycol) monomethyl ether (MPEG) with 2-bromoisobutyryl bromide. Then, poly(2-(diethylamino)ethyl methacrylate) (PDMAEMA) was introduced by a sequential ATRP process to obtain the triblock copolymers. These copolymers with varied compositions, molecular weights and polydispersities were characterized by 1H NMR and GPC. Variable temperature ultraviolet analysis was employed to test their stimuli-sensitive properties. These block copolymers exhibited distinct thermo-sensitivity under different molecular compositions or solution conditions. The resistance to the non-specific protein adsorption of the triblock copolymers was evaluated, and excellent antifouling property occurred. This can be attributed to surface hydration via hydrogen bonds between PEG and water molecules and the surface hydration via ionic-induction between PSBMA and water molecules. The synergistic effect resulted in an effective reduction of protein adsorption. These copolymers have potential applications as antifouling and antibacterial agents.

A facile procedure to fabricate superhydrophobic surfaces based on nano calcium carbonate–polymer composites has been described. The hydrophobicity of the resulting surfaces can be tuned by varying the weight ratio of nano calcium carbonate–polymer composites. The simple and robust strategy can facilitate the fabrication of superhydrophobic surfaces on general substrates.

Ordered poly(3,4-ethylenedioxythiophene) (PEDOT) was successfully prepared by electrochemical polymerization of 3,4-ethylenedioxythiophene in lyotropic liquid crystal phase formed by chitosan in an acetic acid solution. The structure, performance, and morphology of PEDOT were characterized by infrared absorption spectra, cyclic voltammograms, polarizing optical microscopy, and scanning electron microscopy. The ordered pure PEDOT film with good electrochemical behavior exhibited obvious birefringence.

A versatile method of grafting poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) on the surface of hollow mesoporous silica nanoparticles (HMSN) via surface-initiated atom transfer radical polymerization (SI-ATRP) has been presented. TEM, FT-IR, TGA, XRD, and N2 adsorption–desorption analysis were used for the characterization. The results state that the stimuli-responsive polymer has been successfully grafted onto the surface of HMSN. These hybrid nanoparticles have been proven to have a large storage capacity which can be applied in drug delivery. The external coated PDMAEMA layers act as a storage gate as well as a release switch in response to the stimuli of environment. In this paper, pH-responsive controlled release behavior was focused.

A novel copolymer containing Eu-complex moieties and N-vinylcarbazole (NVK) segments was synthesized and characterized by FT-IR, elemental analysis, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), cyclic voltammetry (CV), UV–vis absorption spectra and photoluminescence (PL) spectra. The copolymer exhibits a high glass transition temperature (Tg = 203 °C), high thermal decomposition temperature (Td = 345 °C) and good hole-transporting ability (HOMO energy level: −5.38 eV). Particularly, the copolymer shows an interesting photoluminescence (PL) feature: whether in solid state or chloroform solution, the copolymer always emits the characteristic emission of Eu3+ due to the 5D0 → 7FJ (J = 0–4) transitions; besides, the copolymer solution emits the characteristic emission of carbazole and the copolymer solid emits the characteristic emission of metalloquinolate. These phenomenons indicate that the NVK segments are not only used as light-harvesting groups to absorb energy and transfer energy to ligand and then to Eu3+, but also as barrier to form a local microenvironment for Eu-complex moieties. Moreover, the microenvironment was studied by PL emission spectra and Judd-Ofelt analysis, indicating that the introduction of NVK segments increases the polarity and asymmetry of the chemical environment of the europium ion.

The electropolymerization and deposition of conjugated polythiophene network films on planar indium tin oxide electrode surfaces were described. The precursor polymer, a polymethacrylate functionalized with thiophene, poly[3-(hexyl methacrylate)]thiophene (P3HMAT), was synthesized and then electropolymerized on ITO substrates in boron trifluoride diethyl etherate (BFEE)/CH2Cl2 (v/v = 6:4) binary solution system, resulting in poly{poly[3-(hexyl methacrylate)]thiophene} (PP3HMAT). The possibility of inter- and intramolecular polymerization resulted in a cross-linking conjugated network microstructure. The fluorescence spectra indicated that PP3HMAT films can be used as yellow-green-light emitters even they could not be dissolved in common solvents. The thermal analyses demonstrated that PP3HMAT has good thermal stability. In addition, the molecular weight and distribution of P3HMAT were characterized by GPC, and the molecular structures of the monomer and the polymers were characterized by 1H NMR and FTIR, and optical properties of the monomer and polymers were characterized by UV–vis spectroscopy.

A novel conjugated polythiophene derivative with polymethacrylate attaching to the polymer backbone via an alkyl spacer was successfully synthesized. A methacrylate-substituted thiophene monomer, 3-(hexyl methacrylate)thiophene was prepared and polymerized by free radical polymerization, followed by an electrochemical polymerization. The resulting polymer as a yellow-green-light emitter, has potential applications in photoelectronics area.

Novel amphiphilic fluorinated ABC-type triblock copolymers composed of hydrophilic poly(ethylene oxide) monomethyl ether (MeOPEO), hydrophobic polystyrene (PSt), and hydrophobic/lipophobic poly(perfluorohexylethyl acrylate) (PFHEA) were synthesized by atom transfer radical polymerization (ATRP) using N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA)/CuBr as a catalyst system. The bromide-terminated diblock copolymers poly(ethylene oxide)-block-polystyrene (MeOPEO-b-PSt-Br) were prepared by the ATRP of styrene initiated with the macroinitiator MeOPEO-Br, which was obtained by the esterification of poly(ethylene oxide) monomethyl ether (MeOPEO) with 2-bromoisobutyryl bromide. A fluorinated block of poly(perfluorohexylethyl acrylate) (PFHEA) was then introduced into the diblock copolymer by a second ATRP process to synthesize a novel ABC-type triblock copolymer, poly(ethylene oxide)-block-polystyrene-block-poly(perfluorohexylethyl acrylate) (MeOPEO-b-PSt-b-PFHEA). These block copolymers were characterized by means of proton nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC). Water contact angle measurements revealed that the polymeric coating of the triblock copolymer (MeOPEO-b-PSt-b-PFHEA) shows more hydrophobic than that of the corresponding diblock copolymer (MeOPEO-b-PSt). Bovine serum albumin (BSA) was used as a model protein to evaluate the protein adsorption property and the triblock copolymer coating posseses excellent protein-resistant character prior to the corresponding diblock copolymer and polydimethylsiloxane. These amphiphilic fluoropolymers can expect to have potential applications for antifouling coatings and antifouling membranes. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

With ammonium persulfate (APS) as the initiator, the kinetics of methyl methacrylate (MMA) grafting polymerization onto flaky aluminum powder (Al) was studied. It was found that the Experimental apparent grafting polymerization rate, Rg = KC Al 0.521 x C APS 0.429 x C 0.978 MMA' was basically consistent with the theoretical result based on the theory of stable polymerization and equivalent activity, R g = KC 0.5 Al x C 0.5 APS x C MMA . The activation energy of grafting, homogenous, and total polymerization rate was calculated as 65.1, 35.4, and 37.5 kJ mol -1 , respectively. It could be validated that the relationship among these activation energies accorded with the theoretical result of parallel reactions.

The self-assembly and photoresponsivity of amphiphilic azobenzene-containing ABA triblock copolymers PA6C m -b-PEG n -b-PA6C m synthesized by atom transfer radical polymerization (ATRP) were reported. Different self-assembly morphologies formed by the gradual addition of water to the copolymer solutions in THF. The formation process and aggregate morphology were characterized by UV-Visible spectroscopy and transmission electron microscope (TEM). The triblock copolymers start to form aggregates at the critical water content (CWC). With the addition of water, the aggregates show different morphologies, such as spherical micelles, vesicles, network-like aggregates, and colloidal spheres, which involves the transformation between primary and secondary aggregates and the association/disassociation of aggregates. Photoresponsive property and aggregation behavior of these copolymers in solution under UV-Visible light irradiation were also investigated.

Poly(trimethylolpropane triacrylate)/flaky aluminum composite particle was prepared by in situ polymerization in order to improve the corrosion resistance and adhesive property of aluminum pigments. The effect of monomer concentration, initiator concentration and feeding mode on the conversion , percentage of grafting and grafting efficiency in the preparation was studied. It was found that poly(trimethylolpropane triacrylate) had been successfully grafted on the surface of flaky aluminum through chemical bond, rather than the simple physical adsorption. Evolved hydrogen detection and pulling experiment showed that the corrosion resistance and adhesive property of composite particle had been markedly enhanced, implying that flaky aluminum had been compactly encapsulated with a layer of poly(trimethylolpropane triacrylate) by in situ polymerization.

To improve its anticorrosion property, aluminum pigment was encapsulated by in situ copolymerization of styrene (St) and maleic acid (MA). It was found that the conversion of monomers (C), the percentage of grafting (PG) and the grafting efficiency (GE) could attain 92%, 12%, 25%, respectively, when m (BPO)/ m (St + MA) = 10% and m (St + MA)/ m (Al) = 10%. The optimum condition for protection factor was studied according to an orthogonal testing. When m (St + MA)/ m (Al) was 20%, the encapsulated aluminum pigment simultaneously showed good anticorrosion property and luster. FTIR, SEM and particle size analysis indicated that aluminum pigment had been successfully encapsulated with styrene–maleic acid copolymer by in situ copolymerization, which remarkably improved its anticorrosion property and the chelate complex formed between SMA and Al(III) was possibly the actual corrosion inhibitor.

4-Arm star side-chain liquid crystalline (LC) polymers containing azobenzene with different terminal substituents were synthesized by atom transfer radical polymerization (ATRP). Tetrafunctional initiator prepared by the esterification between pentaerythritol and 2-bromoisobutyryl bromide was utilized to initiate the polymerization of 6-[4-(4-methoxyphenylazo)phenoxy]hexyl methacrylate (MMAzo) and 6-[4-(4-ethoxyphenylazo)phenoxy]hexyl methacrylate (EMAzo), respectively. The 4-arm star side-chain LC polymer with p-methoxyazobenzene moieties exhibits a smectic and a nematic phase, while that withp-ethoxyazobenzene moieties shows only a nematic phase, which derives of different terminal substituents. The star polymers have similar LC behavior to the corresponding linear homopolymers, whereas transition temperatures decrease slightly. Both star polymers show photoresponsive isomerization under the irradiation with UV-vis light.

Graft copolymers of ethyl cellulose with azobenzene-containing polymethacrylates were synthesized through atom transfer radical polymerization (ATRP). The residual hydroxyl groups on ethyl cellulose were first esterified with 2-bromoisobutyryl bromide to yield 2-bromoisobutyryloxy groups, which was then used to initiate the polymerization of 6-[4-(4-methoxyphenylazo)phenoxy]hexyl methacrylate (MMAzo) in the presence of CuBr/N,N,N',N",N"-pentamethylenetriamine (PMDETA) as catalyst and anisole as solvent. The graft copolymers were characterized by gel permeation chromatography (GPC) and 1 H-NMR. The molecular weights of the graft copolymers increased relatively to the macroinitiator, and the polydispersities were narrow. The thermal and liquid crystalline property of the graft copolymers were investigated by differential scanning calorimeter (DSC) and polarizing optical microscope (POM). Photoresponsive property was studied under the irradiation of UV-vis light in THF solution. The graft copolymers have potential applications, including sensors and optical materials.

ABA-type amphiphilic triblock copolymers composed of poly(ethylene glycol)s (PEGs) with different number-average molecular weights as the hydrophilic blocks (B) and poly{6-[4-(4-ethoxyphenylazo)phenoxy]hexyl methacrylate} (PA6C) as the hydrophobic blocks (A) were prepared via atom transfer radical polymerization. These copolymers were prepared from bromo-terminated macroinitiators based on PEG6000, PEG2000, and PEG600, with CuBr/N,N,N′,N″,N″-pentamethyldiethylenetriamine as the catalytic system, at 85 °C in anisole. The block copolymers were characterized with 1H NMR spectroscopy and gel permeation chromatography. Differential scanning calorimetry measurements were performed to reveal the phase segregation. In contrast to those polymers with similar compositions and structures in previous reports, these amphiphilic copolymers exhibited unusual liquid-crystalline properties over a wide temperature range, being stable even at room temperature. These copolymers showed photoresponsive isomerization under the irradiation of UV–vis light both in THF solutions and in solid films. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2225–2234, 2007

A facile strategy for grafting poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) on the surface of hydroxy carbonate apatite (HCA) nanoparticles via surface-initiated ATRP has been presented. SEM...

A one-step dip coating process was applied to fabricate a transparent superhydrophobic coating on the surface of paper using silica nanoparticles modified with long-chain hydrocarbon hexadecyltrimethoxysilane in an ethanolic solution.