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1.
ACS Appl Mater Interfaces ; 15(25): 29700-29712, 2023 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-37306970

RESUMEN

Polysarcosine (PSar) is an electrically neutral and excellently hydrophilic polypeptoid showing limited interaction with proteins and cells, which possesses better biocompatibility compared with polyethylene glycol. However, the immobilization of PSar is difficult due to the high water solubility. Herein, lysine-sarcosine PiPo, which was the random copolymer of lysine and sarcosine (PLS), was synthesized via a phosgene-free and water-tolerable polymerization of N-phenyloxycarbonyl-amino acids for the first time. PLS was immobilized by tannic acid (TA) on the polysulfone (PSf) membrane for a short time to obtain a neutral surface. The modified membrane showed improved hydrophilicity, decreased protein adsorption, and low cytotoxicity. Moreover, barely any hemolysis, no platelet adhesion, prolonged clotting time, and low complement activation further suggested good hemocompatibility. In order to improve the antifouling ability of the membrane under pressure, the neutral surface was oxidized by sodium periodate, which accelerated the chemical reaction between amino groups in PLS and phenolic hydroxyl groups in TA. Meanwhile, carboxyl groups generated due to the decomposition of TA and a negatively charged surface were obtained. While maintaining the good properties of the unoxidized one, the hydrophilicity of the oxidized membrane was improved and the clotting time was further prolonged. Besides, the filtration recovery of the oxidized membrane was improved remarkably. This approach of rapid immobilization of PSar has great potential for applications in the biomedical area, especially for blood-contacting materials.


Asunto(s)
Lisina , Sarcosina , Proteínas/química , Polietilenglicoles/química , Agua/química , Propiedades de Superficie
2.
J Colloid Interface Sci ; 613: 234-243, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35042024

RESUMEN

In this study, a blend membrane consisting of polyvinylidene fluoride (PVDF) and tertiary amine containing random copolymer poly(methyl methacrylate-r-dimethylamino-2-ethyl methacrylate) (P(MMA-r-DMAEMA)) was fabricated and utilized as an adsorptive membrane for micropollutants (anionic dye and heavy metal ions) removal from aqueous solutions. Cross-linking the random copolymer by p-xylylene dichloride (XDC) produced the membrane with improved copolymer retention ratio and stability, while slightly variated physicochemical properties. Besides, the fluxes of crosslinked blend membranes dramatically increased from 0.7 ± 0.1 L/(m2h) to 118.6 ± 5.9 L/(m2h). Then the present blend membrane was carried out adsorption and filtration experiments to investigate the influence of various of operation parameters including initial solution pH value, contacting time, initial solution concentration, and recycling efficiency on micropollutants removal. The experimental results showed that the removal of the anionic dyes and heavy metal ions on this tertiary amine containing blend membrane was a pH-dependent process with the maximum adsorption capacity at the initial solution pH of 3.5 for anionic dyes and 6.0 for metal ions, respectively. The membrane showed highly efficient capture of sunset yellow (above 99%). Meanwhile, the captured sunset yellow was recovered and concentrated with a small volume of alkaline solutions at pH 10.0, which simultaneously regenerated the membrane for its reuse. In a 3-cycle capture-recovery test, the membrane demonstrated a high sunset yellow recovery ratio and a volumetric concentration ratio as high as 400%. Our study provides an alternative strategy for functionalized membrane fabrication, micropollutants removal and recovery.


Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Adsorción , Membranas Artificiales , Ultrafiltración , Contaminantes Químicos del Agua/análisis
3.
Nanoscale ; 14(35): 12789-12803, 2022 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-36004750

RESUMEN

With the continuous emergence of drug-resistant pathogens, new strategies with high antibacterial efficacy are urgently needed. Herein, five cationic nano-sized hyperbranched polymers (CNHBPs) with cationic functional groups have been constructed, and their antibacterial mechanism has been studied in detail. CNHBPs bearing secondary ammonium salt groups and long alkyl chains (S12-CNHBP) exhibited weak antibacterial and antibiofilm ability, while CNHBPs bearing quaternary ammonium salt groups and long alkyl chains (Q12-CNHBP) showed the highest antimicrobial and strongest antibiofilm activities. ζ potential and isothermal titration microcalorimetry (ITC) results suggest that the negatively charged surfaces of bacterial cells provided Q12-CNHBP with a higher intrinsic electrostatic driving force for bacterial killing than that with S12-CNHBP. Fluorescent tracing and morphological observations indicate that the bacterial genome might be another antibacterial target for S12-CNHBP in addition to the cell wall and membrane, which are mainly antibacterial targets for Q12-CNHBP, making it less likely to induce bacterial resistance. Surprisingly, Q12-CNHBP exhibited superior in vivo therapeutic efficacy in a mouse wound model of methicillin-resistant Staphylococcus aureus (MRSA) infection with low toxicity during treatment. These advantages and ease of preparation will undoubtedly distinguish Q12-CNHBP as a new class of suitable candidates to combat multidrug-resistant pathogen infections. This study opens up a new avenue for exploiting antibacterial biomaterials to treat infections caused by drug-resistant bacteria.


Asunto(s)
Antiinfecciosos , Staphylococcus aureus Resistente a Meticilina , Animales , Antibacterianos/química , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Bacterias , Materiales Biocompatibles , Cationes , Ratones , Pruebas de Sensibilidad Microbiana , Polímeros/química , Polímeros/farmacología , Compuestos de Amonio Cuaternario/química , Cicatrización de Heridas
4.
Langmuir ; 27(23): 14180-7, 2011 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-22011109

RESUMEN

This study aims to explore the fundamental surface characteristics of polydopamine (pDA)-coated hydrophobic polymer films. A poly(vinylidene fluoride) (PVDF) film was surface modified by dip coating in an aqueous solution of dopamine on the basis of its self-polymerization and strong adhesion feature. The self-polymerization and deposition rates of dopamine on film surfaces increased with increasing temperature as evaluated by both spectroscopic ellipsometry and scanning electronic microscopy (SEM). Changes in the surface morphologies of pDA-coated films as well as the size and shape of pDA particles in the solution were also investigated by SEM, atomic force microscopy (AFM), and transmission electron microscopy (TEM). The surface roughness and surface free energy of pDA-modified films were mainly affected by the reaction temperature and showed only a slight dependence on the reaction time and concentration of the dopamine solution. Additionally, three other typical hydrophobic polymer films of polytetrafluoroethylene (PTFE), poly(ethylene terephthalate) (PET), and polyimide (PI) were also modified by the same procedure. The lyophilicity (liquid affinity) and surface free energy of these polymer films were enhanced significantly after being coated with pDA, as were those of PVDF films. It is indicated that the deposition behavior of pDA is not strongly dependent on the nature of the substrates. This information provides us with not only a better understanding of biologically inspired surface chemistry for pDA coatings but also effective strategies for exploiting the properties of dopamine to create novel functional polymer materials.


Asunto(s)
Dopamina/química , Indoles/síntesis química , Membranas Artificiales , Polímeros/síntesis química , Polivinilos/química , Interacciones Hidrofóbicas e Hidrofílicas , Indoles/química , Estructura Molecular , Tamaño de la Partícula , Polímeros/química , Propiedades de Superficie
5.
J Colloid Interface Sci ; 593: 315-322, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33744540

RESUMEN

In this study, positively charged monomers were grafted onto negatively charged membranes via UV radiation to improve the antifouling/antibiofouling properties of the polymeric membrane and the stability of the modification layer. The surface properties, morphologies, antifouling and antibiofouling properties, and stability of the modified membranes were systematically characterized. Results indicated that the introduction of [2-(methacryloyloxy) ethyl] trimethylammonium chloride (MTAC) monomers onto polyethersulfone (PES)/sulfonated polyethersulfone (SPES) membranes effectively increased the surface hydrophilicity. Meanwhile, the surfaces were neutralized with ~0 mV zeta potential in pH 3-10. Moreover, the formation of a polyampholytic copolymer and the antibacterial ability of MTAC considerably improved the antibiofouling properties of the modified membranes. The MTAC-grafted PES/SPES membranes showed excellent antifouling/antibiofouling properties during the treatment of various types of wastewater, including bovine serum albumin solution, oil/water emulsion, and bacterial suspension. Therefore, this study provides a simple and effective method of constructing stable and antifouling membranes for sustainable water treatment.


Asunto(s)
Incrustaciones Biológicas , Incrustaciones Biológicas/prevención & control , Interacciones Hidrofóbicas e Hidrofílicas , Membranas Artificiales , Albúmina Sérica Bovina , Propiedades de Superficie
6.
J Colloid Interface Sci ; 584: 225-235, 2021 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-33069021

RESUMEN

To overcome the organic-/bio- fouling of the membrane, a dual-functional ultrafiltration membrane containing quaternary ammonium and zwitterionic polymers via quaternization and surface radical polymerization was designed, and its antifouling and antibacterial behavior was studied. In this work, poly(vinylidene fluoride)/poly(methyl methacrylate-co-dimethylamino-2-ethyl methacrylate) (PVDF/P(MMA-co-DMAEMA)) blend membrane was quaternized by p-chloromethyl styrene (p-CMS), and the double bonds were introduced onto the membrane surface, which further participated in the polymerization of zwitterionic monomers on the membrane surface. The results indicated that the resultant membrane exhibited obviously improved hydrophilicity and weak positive charge (isoelectric point, 7.49). The membrane presented higher flux recovery ratio and lower protein adhesion compared with the pure PVDF membrane. Meanwhile, the membrane showed high-efficiency broad-spectrum antibacterial performance, that is, the bacteria killing efficiency of S. aureus and E. coli reached 98.2% and 97.0%, respectively. Moreover, the membrane effectively inhibited bacterial adhesion, which is important for the long-term antibacterial properties of membrane. This antifouling and antibacterial PVDF membrane may have potential in the long-term filtration process, especially when dealing with microbiologically contaminated water.


Asunto(s)
Compuestos de Amonio , Incrustaciones Biológicas , Antibacterianos/farmacología , Incrustaciones Biológicas/prevención & control , Escherichia coli , Polímeros , Staphylococcus aureus
7.
J Chromatogr A ; 1563: 198-206, 2018 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-29886000

RESUMEN

Energy-efficient and time-saving process for recovery of hazardous dyes from wastewater is highly desired in dyeing industry. In this work, poly(N-vinyl imidazole) (PVI) gel-filled membrane adsorbers were developed for highly efficient recovery of dyes through adsorption filtration. The membrane adsorbers were fabricated via dip-coating of Nylon macroporous membranes in PVI solutions followed by quaternization crosslinking with p-xylylene dichloride (XDC). Physicochemical characterizations indicated that PVI gel was successfully filled and fixed inside the Nylon matrix. In optimized conditions. The treating capacity of membrane adsorbers to typical dye sunset yellow (25 ppm of the feed concentration) reached up to 197 mg/g with the removal ratio >99%. Both the treating capacity and the removal ratio were kept steady even when the permeation flux was as high as 1000 L/m2 h. The membrane adsorbers developed in this work were able to not only remove anionic dyes from water, but also separate anionic dyes from cationic ones. The zeta potential and adsorption tests showed that the electrostatic interaction between PVI gel and dye molecules was responsible for the high removal efficiencies to anionic dyes. The membrane adsorbers can be regenerated effectively with NaOH solution and demonstrated good stability in both acidic and alkaline conditions.


Asunto(s)
Colorantes/química , Geles/química , Imidazoles/química , Polivinilos/química , Contaminantes Químicos del Agua/química , Adsorción , Compuestos Azo/química , Compuestos Azo/aislamiento & purificación , Colorantes/aislamiento & purificación , Filtración , Concentración de Iones de Hidrógeno , Membranas Artificiales , Contaminantes Químicos del Agua/aislamiento & purificación
8.
Colloids Surf B Biointerfaces ; 57(2): 189-97, 2007 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-17379486

RESUMEN

A styrene-maleic anhydride (SMA) alternating copolymer with ultrahigh molecular weight (M(w)>10(6)) synthesized in super critical carbon dioxide (SC CO(2)) medium was used as hydrophilic polymeric additive in the preparation of polyethersulfone (PES) membranes. The PES/SMA blend membranes were prepared by immersion precipitation process. X-ray photoelectronic spectroscopy (XPS) measurements confirmed that the hydrolyzed SMA preferentially segregated to membrane-coagulant interface during membrane formation. For the PES/SMA blend membranes, no big change was observed in the cross-sectional structure and the mechanical properties were well maintained after SMA addition except that a thicker top layer was formed. The surface morphology analysis by atomic force microscopy (AFM) showed that the membrane surface roughness increased with the added SMA amount. The results of water contact angle, water absorbance measurements and static protein adsorption experiments revealed that the surface enrichment of SMA endowed PES/SMA blend membranes with significantly improved surface hydrophilicity and protein-adsorption resistance.


Asunto(s)
Anhídridos Maleicos/química , Membranas Artificiales , Polímeros/química , Poliestirenos/química , Proteínas/química , Sulfonas/química , Adsorción , Microscopía de Fuerza Atómica , Microscopía Electrónica de Rastreo , Peso Molecular , Propiedades de Superficie
9.
Water Res ; 121: 197-203, 2017 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-28535433

RESUMEN

We designed a highly selective surface coating to achieve enhanced rejection of endocrine disrupting compounds (EDCs) by nanofiltration membranes. A commercial NF90 membrane was first coated with polydopamine (PDA) followed by in situ immobilization of silver nanoparticles (AgNPs). This PDA/AgNPs coating greatly improved EDC rejection at the expense of slight water permeability loss (4-10%). This improvement in rejection can be attributed to a combination of enhanced size exclusion and suppressed hydrophobic interaction. A resistance-in-series analysis further reveals that the coating was highly permeable to water but highly resistant to EDCs, leading to an EDC selectivity that was an order of magnitude greater than those of the bare PDA coating and the base membrane NF90. The current study provides important insights into the design of highly selective coatings for effective retention of targeted trace organic contaminants.


Asunto(s)
Disruptores Endocrinos , Membranas Artificiales , Purificación del Agua , Interacciones Hidrofóbicas e Hidrofílicas , Plata
10.
J Colloid Interface Sci ; 437: 124-131, 2015 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-25313475

RESUMEN

Four tertiary amine based amphiphilic copolymers with similar composition but different sequence structures in terms of diblock (Poly(dimethylamino-2-ethyl methacrylate-b-methyl methacrylate) (P(MMA-b-DMAEMA))), triblock (P(DMAEMA-b-MMA-b-DMAEMA)), four-armed diblock (P(MMA-b-DMAEMA)4) and random (P(MMA-r-DMAEMA)) were synthesized and used for fabricating functional porous membranes by blending method. The retention ratios and surface enrichment ratios of the copolymers in blend membranes were determined by hydrogen nuclear magnetic resonance ((1)H-NMR) and X-ray photoelectron spectroscopy (XPS). The composition of the formed membranes was investigated and the durability was experimentally tested. The hydrophilicity of the membranes was evaluated by water contact angle measurement. The performance of membranes under different conditions including water fluxes at different pH and various ionic strength, the adsorption capabilities for Cr(VI) and negatively charged dye sunset yellow at different pH was studied. The results show that tertiary amine based amphiphilic copolymers with block and multi-armed sequence structures enable the blend membranes with higher copolymer retention ratios, more surface tertiary amine groups contents and better composition stability as well as more sensitive to the variation of pH, ionic strength, higher equilibrium anions, and negatively charged dyes uptakes.


Asunto(s)
Aminas/química , Membranas Artificiales , Adsorción , Concentración de Iones de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Microscopía Electrónica de Rastreo , Concentración Osmolar , Espectroscopía de Fotoelectrones , Espectroscopía de Protones por Resonancia Magnética
11.
J Colloid Interface Sci ; 422: 38-44, 2014 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-24655826

RESUMEN

Polyethersulfone (PES) membranes with improved hemocompatibility were prepared via solid-liquid interface aminolysis and heparinization. Reactive amino groups were generated by immersing solid PES membranes in proper diamine solution. Heparin was covalent immobilized on the surface via amide bond. The feasibility of surface aminolysis for the introduction of amino groups and the effectiveness for further heparin immobilization were confirmed by surface group analysis. The effect of aminolysis time on surface amino group concentration and bulk mechanical properties was investigated. The surface amino group concentration determined the amount and bioactivity of immobilized heparin chains. SEM images suggested that both the aminolysis and heparinization reaction had little effect on the surface morphology of PES membranes. Contact angle measurement, surface charge analysis, protein and platelet adsorption/adhesion experiment were applied to study the surface properties. The results showed that the heparinized PES membranes displayed enhanced hydrophilicity and hemocompatibility, indicating potential application in blood purification and other blood contacting fields.


Asunto(s)
Aminas/química , Materiales Biocompatibles , Sangre , Heparina/química , Membranas Artificiales , Polímeros/química , Sulfonas/química , Propiedades de Superficie
12.
Carbohydr Polym ; 106: 403-9, 2014 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-24721095

RESUMEN

Carboxymethyl cellulose (CMC)-modified silica nanocomposites were prepared via in situ incorporation of modified silica during the ionic complexation between CMC and poly(2-methacryloyloxy ethyl trimethylammonium chloride) (PDMC). Ionic bonds were introduced between the poly(2-acrylamido-2-methylproanesulfonic acid) modified silica (SiO2-PAMPS) and the polyelectrolyte complex (PEC) matrix. The PEC nanocomposites (PECNs) and their membranes (PECNMs) were characterized with Fourier transform-infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and tensile testing. PECNM containing 5 wt.% SiO2-PAMPS showed a tensile strength of 68 MPa and elongation at break of 7.1%, which were 1.9 and 2.6 times as high as those of pristine PEC membranes, respectively. Moreover, the pervaporation performance of as-prepared PECNMs was evaluated with dehydration of 10 wt.% aqueous isopropanol mixtures, and the PECNMs exhibited a flux of 2,400 gm(-2)h(-1) with a high separation factor of 4491 at 70°C.


Asunto(s)
Carboximetilcelulosa de Sodio/química , Electrólitos/química , Membranas Artificiales , Metacrilatos/síntesis química , Nanocompuestos/química , Polímeros/química , Ácidos Sulfónicos/química , 2-Propanol/química , Desecación , Interacciones Hidrofóbicas e Hidrofílicas , Ensayo de Materiales , Metacrilatos/química , Microscopía Electrónica de Rastreo , Dióxido de Silicio , Soluciones , Espectroscopía Infrarroja por Transformada de Fourier , Electricidad Estática , Resistencia a la Tracción , Termogravimetría , Agua/química
13.
ACS Appl Mater Interfaces ; 5(24): 12895-904, 2013 Dec 26.
Artículo en Inglés | MEDLINE | ID: mdl-24313803

RESUMEN

A facile and versatile approach for the preparation of antifouling and antimicrobial polymer membranes has been developed on the basis of bioinspired polydopamine (PDA) in this work. It is well-known that a tightly adherent PDA layer can be generated over a wide range of material surfaces through a simple dip-coating process in dopamine aqueous solution. The resulting PDA coating is prone to be further surface-tailored and functionalized via secondary treatments because of its robust reactivity. Herein, a typical hydrophobic polypropylene (PP) porous membrane was first coated with a PDA layer and then further modified by poly(N-vinyl pyrrolidone) (PVP) via multiple hydrogen-bonding interactions between PVP and PDA. Data of water contact angle measurements showed that hydrophilicity and wettability of the membranes were significantly improved after introducing PDA and PVP layers. Both permeation fluxes and antifouling properties of the modified membranes were enhanced as evaluated in oil/water emulsion filtration, protein filtration, and adsorption tests. Furthermore, the modified membranes showed remarkable antimicrobial activity after iodine complexation with the PVP layer. The PVP layer immobilized on the membrane had satisfying long-term stability and durability because of the strong noncovalent forces between PVP and PDA coating. The strategy of material surface modification reported here is substrate-independent, and applicable to a broad range of materials and geometries, which allows effective development of materials with novel functional coatings based on the mussel-inspired surface chemistry.


Asunto(s)
Antiinfecciosos/química , Indoles/química , Polímeros/química , Povidona/química , Antiinfecciosos/farmacología , Hidrógeno/química , Enlace de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Aceites/química , Staphylococcus aureus/efectos de los fármacos , Propiedades de Superficie , Agua/química , Humectabilidad
14.
Colloids Surf B Biointerfaces ; 110: 36-44, 2013 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-23707848

RESUMEN

Here we report the fabrication of a novel heparinized copper hydroxide (Cu(OH)2) nanofiberous membrane with satisfying hemocompatibility and antibacterial properties. The positively charged Cu(OH)2 nanofibers were prepared in a weakly alkaline copper nitrate solution in the presence of 2-aminoethanol. A heparin (Hep) solution was then added dropwise into the solution of nanofibers to immobilize negatively charged heparin onto the Cu(OH)2 nanofibers by electrostatic interaction. A composite Hep@Cu(OH)2 nanofiberous membrane was prepared by filtration and deposition of the heparinized nanofibers onto a polysulfone (PSF) porous membrane. Chemical composition analysis of membrane surface using X-ray photoelectron spectroscopy (XPS) confirmed the successful immobilization of heparin on Cu(OH)2 nanofibers. The amount of immobilized heparin on nanofiberous membrane was determined by a colorimetric assay of toluidine blue dye and the results showed that the amount of immobilized heparin was strongly dependent on the heparin dosage in reaction solution. The results of contact angle measurement indicated that the hydrophilicity of Cu(OH)2 nanofiberous membranes was enhanced by the immobilization of heparin. The adhesion, activation and transmutation of platelets on Hep@Cu(OH)2 membrane were suppressed remarkably due to the introduction of heparin, which suggested that the Hep@Cu(OH)2 membranes had good hemocompatibility. In addition, Cu(OH)2 and Hep@Cu(OH)2 nanofiberous membranes exhibited very good antibacterial activities against Escherichia coli and Staphyloccocus aureus.


Asunto(s)
Antibacterianos/química , Materiales Biocompatibles/química , Cobre/química , Heparina/química , Hidróxidos/química , Nanofibras/química , Tamaño de la Partícula , Porosidad , Propiedades de Superficie
15.
Colloids Surf B Biointerfaces ; 86(1): 111-8, 2011 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-21497492

RESUMEN

Based on the self-polymerization and strong adhesion characteristics of dopamine in aqueous solution, a novel and convenient approach was developed to immobilize protein onto porous polyethylene (PE) membranes. A thin polydopamine (pDA) layer was formed and tightly coated onto PE membrane by dipping simply the membrane into dopamine aqueous solution for a period of time. Subsequently, bovine serum albumin (BSA) was bound onto the obtained PE/pDA composite membranes via the coupling between BSA and the reactive polydopamine layer. The firm immobilization of polydopamine layer and BSA was verified by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The results of water contact angle measurement showed that the hydrophilicity of PE membrane was significantly improved after coating polydopamine and binding BSA. The experiments of blood platelet adhesion indicated that BSA-immobilized PE membrane had better blood compatibility than the unmodified PE and the PE/pDA composite membranes. The investigations on hepatocyte cultures and cell viability revealed that the polydopamine coating endowed PE membrane with significantly improved cell compatibility. Compared to BSA surface, polydopamine surface is more favorable for cell adhesion, growth, and proliferation.


Asunto(s)
Dopamina/química , Membranas Artificiales , Polietileno/química , Polímeros/química , Albúmina Sérica Bovina/química , Animales , Bovinos , Modelos Teóricos , Porosidad , Propiedades de Superficie
16.
J Colloid Interface Sci ; 363(2): 676-81, 2011 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-21862031

RESUMEN

Superhydrophilic organic/inorganic hybrid surfaces have been fabricated on blend membranes of poly(vinylidene fluoride) (PVDF) and poly(styrene-alt-maleic anhydride) (SMA). The blend membranes were prepared from PVDF/SMA mixed solution with N,N-dimethylacetamide (DMAc) as solvent by immersion-precipitation phase inversion process. The gained blend membranes were immersed into γ-aminopropyltriethoxysilane (APTS) solution to generate SMA/silica hybrid surfaces by the reaction between anhydrides and APTS. The hybrid surfaces chemical compositions, morphologies and hydrophilicity were investigated in detail. It demonstrates that the hybrid surfaces possess micro-nano hierarchical structure and display superhydrophilicity property and good stability. Finally, the reaction and formation mechanism of the superhydrophilicity hybrid surface was discussed.


Asunto(s)
Maleatos/química , Membranas Artificiales , Poliestirenos/química , Polivinilos/química , Dióxido de Silicio/química , Interacciones Hidrofóbicas e Hidrofílicas , Tamaño de la Partícula , Propiedades de Superficie
17.
Huan Jing Ke Xue ; 30(1): 160-5, 2009 Jan.
Artículo en Zh | MEDLINE | ID: mdl-19353875

RESUMEN

A free-end comb-like hollow fiber membrane bioreactor was applied to treat wastewater. The results clearly showed that membrane fouling, defined as permeate flux decline, was greatly influenced by membrane module configuration. The permeate flux decline was much less for module b, demonstrating the superiority of module b over module a. Its permeate flux could be maintained in the range of 4.0 to 8.0 L x (m2 x h)(-1) under the operating conditions that temperature was 22-26 degrees C, the mixed liquor suspended solids (MLSS) concentration was 7500-10500 mg/L, aeration intensity was 200 L/h, suction time/ suspended time ratio was 9 min/1 min and suction pressure was 0.02 MPa. As this novel kind of membrane module resulted in high air scouring efficiency, relatively low aeration intensity was needed for the MBR maintenance. In addition, the permeate flux varied a little when suction time/ suspended time ratio changed from 12 min/1 min to 6 min/1 min. The performances of several different cleaning methods were tested and the results indicated that water cleaning + chemical cleaning + ethanol soaking had the best cleaning efficiency. SEM images clearly showed that the membrane surface became cleaner and the membrane holes became more visible after water cleaning + chemical cleaning, compared with water cleaning solely.


Asunto(s)
Reactores Biológicos/microbiología , Membranas Artificiales , Aguas del Alcantarillado/química , Eliminación de Residuos Líquidos/métodos , Biodegradación Ambiental , Diseño de Equipo
18.
Colloids Surf B Biointerfaces ; 69(1): 152-5, 2009 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-19117736

RESUMEN

Based on the strong adhesive behavior of poly(3,4-dihydroxy-l-phenylalanine) (or poly(DOPA)) on solid surface, poly(vinylidene fluoride) (PVDF) microporous membranes were surface-modified by the self-polymerization of DOPA in aqueous solution. Subsequently, heparin was immobilized covalently onto the obtained PVDF/poly(DOPA) composite membranes by the coupling between heparin and poly(DOPA) coating. The modified membranes were subjected to a long-term washing, and the firm immobilization of poly(DOPA) and heparin was confirmed by X-ray photoelectron spectroscopy (XPS). The results of water contact angle measurements showed that the hydrophilicity of PVDF membranes was significantly improved by the incorporation of poly(DOPA) and heparin. The effects of poly(DOPA) and heparin on membrane surface morphologies were also investigated by scanning electron microscopy (SEM).


Asunto(s)
Dihidroxifenilalanina/análogos & derivados , Dihidroxifenilalanina/química , Heparina/metabolismo , Proteínas Inmovilizadas/metabolismo , Membranas Artificiales , Polímeros/química , Polivinilos/química , Microscopía Electrónica de Rastreo , Porosidad , Análisis Espectral , Propiedades de Superficie , Agua/química
19.
Langmuir ; 23(10): 5779-86, 2007 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-17408299

RESUMEN

To endow hydrophobic poly(vinylidene fluoride) (PVDF) membranes with reliable hydrophilicity and protein resistance, an amphiphilic hyperbranched-star polymer (HPE-g-MPEG) with about 12 hydrophilic arms in each molecule was synthesized by grafting methoxy poly(ethylene glycol) (MPEG) to the hyperbranched polyester (HPE) molecule using terephthaloyl chloride (TPC) as the coupling agent and blended with PVDF to fabricate porous membranes via phase inversion process. The chemical composition changes of the membrane surface were confirmed by X-ray photoelectron spectroscopy (XPS), and the membrane morphologies were measured by scanning electron microscopy (SEM). Water contact angle, static protein adsorption, and filtration experiments were used to evaluate the hydrophilicity and anti-fouling properties of the membranes. It was found that MPEG segments of HPE-g-MPEG enriched at the membrane surface substantially, while the water contact angle decreased as low as 49 degrees for the membrane with a HPE-g-MPEG/PVDF ratio of 3/10. More importantly, the water contact angle of the blend membrane changed little after being leached continuously in water at 60 degrees C for 30 days, indicating a quite stable presence of HPE-g-MPEG in the blend membranes. Furthermore, the blend membranes showed lower static protein adsorption, higher water and protein solution fluxes, and better water flux recovery after cleaning than the pure PVDF membrane.


Asunto(s)
Membranas Artificiales , Polietilenglicoles/química , Polivinilos/química , Albúmina Sérica Bovina/química , Adsorción , Animales , Bovinos , Interacciones Hidrofóbicas e Hidrofílicas
20.
Biomacromolecules ; 6(2): 1041-7, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-15762676

RESUMEN

A fluorescent, magnetic composite poly(styrene-maleic anhydride) microsphere, suitable for conjugation with polysaccharide, was synthesized using magnetite/europium phthalate particles as seeds by copolymerization of styrene and maleic anhydride. The magnetite/europium phthalate particles were wrapped up by poly(ethylene glycol), which improved the affinity between the seed particles and the monomers. The composite microspheres obtained, with a diameter of 0.15-0.7 microm, contain 586-1013 microg of magnetite/g of microsphere and 0.5-16 mmol surface anhydride groups/g of microsphere. Heparin was conjugated with the reactive surface anhydride groups on the surface of the microspheres by covalent binding to obtain a fluorescent, magnetic, polysaccharide-based microsphere. The microspheres not only retain their bioactivities but also provide magnetic susceptibility and fluorescence. They can be used as a carrier with magnetic orientation and fluorescence tracer for potent drug targeting. The orientation, tracer, and anticoagulation of the fluorescence, magnetic, polysaccharide-based microspheres were studied. The anticoagulant activity of the microspheres and heparin binding capacity reached 54,212.8 U and 607.1 mg/g of dry microspheres. The activity recovery was 50.2%. The anticoagulant activity of the microspheres increases with the increase of the conjugated heparin on the surface of the microspheres and the decrease of the microsphere size. Furthermore, The fluorescent, magnetic, polysaccharide-based microspheres can be easily transported to a given position in a magnetic field and traced via their fluorescence.


Asunto(s)
Anticoagulantes/administración & dosificación , Portadores de Fármacos/síntesis química , Polisacáridos/síntesis química , Portadores de Fármacos/química , Óxido Ferrosoférrico , Fluorescencia , Heparina/administración & dosificación , Heparina/química , Hierro , Magnetismo , Anhídridos Maleicos , Microesferas , Nanoestructuras , Óxidos , Ácidos Ftálicos , Polisacáridos/química , Poliestirenos/síntesis química , Poliestirenos/química
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