共查询到20条相似文献,搜索用时 62 毫秒
1.
LingShu Wan BeiBei Ke XiaoKai Li XiangLin Meng LuYao Zhang ZhiKang Xu 《中国科学B辑(英文版)》2009,52(7):969-974
Highly ordered honeycomb-patterned polystyrene (PS)/poly(ethylene glycol) (PEG) films were prepared by a water-assisted method
using an improved setup, which facilitated the formation of films with higher regularity, better reproducibility, and larger
area of honeycomb structures. Surface aggregation of hydrophilic PEG and adsorption of bovine serum albumin (BSA) on the honeycomb-patterned
films were investigated. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) were used to
observe the surface morphologies of the films before and after being rinsed with water. As confirmed by the FESEM images and
the AFM phase images, PEG was enriched in the pores and could be gradually removed by water. The adsorption of fluorescence-labeled
BSA on the films was studied in visual form using laser scanning confocal microscopy. Results clearly demonstrated that the
protein-resistant PEG was selectively enriched in the pores. This water-assisted method may be a latent tool to prepare honeycomb-patterned
biofunctional surfaces.
Supported by the National Natural Science Foundation of China (Grant No. 50803053), the National Natural Science Foundation
of China for Distinguished Young Scholars (Grant No. 50625309), the National Postdoctoral Science Foundation of China (Grant
Nos. 20070421172 & 20081466) and the National Undergraduate Innovative Test Program 相似文献
2.
Francesc Estrany David Aradilla Ramn Oliver Elaine Armelin Carlos Alemn 《European Polymer Journal》2008,44(5):1323-1330
Multilayered films formed by 3, 5 and 7 alternated layers of poly(3,4-ethylenedioxythiophene) and poly(N-methylpyrrole) have been prepared by chronoamperometry under a constant potential of 1.4 V using a layer-by-layer electrodeposition technique. In order to examine influence of the interface:bulk dimensional ratio, the thickness of the yielded films was reduced from the submicrometric to the nanometric scale by decreasing the polymerization time of each layer from 100 s to 10 s. The electroactivity, electrochemical characteristics and morphologies of the resulting multilayered films have been compared with those obtained for both single-component poly(3,4-ethylenedioxythiophene) films prepared using identical experimental conditions and previously reported multilayered films with thickness within the micrometric scale [Estrany F, Aradilla D, Oliver R, Alemán C. Eur Polym J 2007;43:1876]. 相似文献
3.
Poly(aniline) (PANi) and poly(γ-glutamic acid) (γ-PGA) have been synthesized by enzymatic catalysis and natural bacterial reactions, respectively. Layer-by-layer films have been prepared on glass or quartz slides by alternative immersions of the substrate in dilute solutions of γ-PGA and PANi, with several rinsing in between each deposition. UV-vis spectroscopy has been used to follow the evolution of the self-assembly process as well as to characterize the oxidative states of PANi. The linear dependence of the absorbance vs. the number of layers indicates a constant increase of thickness layer-by-layer. The morphology of the multilayer films, analyzed by atomic force microscopy, is granular type. Enzymatically synthesized PANi nanofilms present good electrical conductivity while γ-PGA acts as an insulating material. These differences in electrical properties and the possibility to obtain alternated multilayered films permit the construction of entirely “biological” nanocapacitors. 相似文献
4.
New approach on the development of plasticized polylactide (PLA): Grafting of poly(ethylene glycol) (PEG) via reactive extrusion 总被引:4,自引:0,他引:4
Fatima Hassouna Jean-Marie Raquez Frédéric Addiego Philippe Dubois Valérie Toniazzo David Ruch 《European Polymer Journal》2011,47(11):2134-2144
In this work, new ways of plasticizing polylactide (PLA) with low molecular poly(ethylene glycol) (PEG) were developed to improve the ductility of PLA while maintaining the plasticizer content at maximum 20 wt.% PLA. To this end, a reactive blending of anhydride-grafted PLA (MAG-PLA) copolymer with PEG, with chains terminated with hydroxyl groups, was performed. During the melt-processing, a fraction of PEG was grafted into the anhydride-functionalized PLA chains. The role of the grafted fraction was to improve the compatibility between PLA and PEG. Reactive extrusion and melt-blending of neat and modified PLA with PEG did not induce any dramatic drop of PLA molecular weight. The in situ reactive grafting of PEG into the modified PLA in PLA/PEG blends showed a clear effect on the thermal properties of PLA. It was demonstrated by DSC that the mobility gained by PLA chains in the plasticized blends yielded crystallization. The grafting of a fraction of PEG into PLA did not affect this process. However, DSC results obtained after the second heating showed an interesting effect on the Tg when 20 wt.% PEG were melt blended with neat PLA or 10 wt.% MAG-PLA. In the latter case, the Tg displayed by the reactive blend was shifted to even lower temperatures at around 14 °C, while the Tg of neat PLA and PLA blended with 20 wt.% PEG was around 60 and 23 °C, respectively. Regarding viscoelastic and viscoplastic properties, the presence of MAG-PLA does not significantly influence the behavior of plasticized PLA. Indeed, with or without MAG-PLA, elastic modulus and yield stress decrease, while ultimate strain increases with the addition of PEG into PLA. 相似文献
5.
The influence of poly(ethylene glycol) (PEG) plasticiser content and molecular weight on the physicochemical properties of films cast from aqueous blends of poly(methyl vinyl ether-co-maleic acid) was investigated using thermal analysis, swelling studies, scanning electron microscopy (SEM) and attenuated total reflectance (ATR)-Fourier transform infrared (FTIR) spectroscopy. FTIR spectroscopy revealed a shift of the CO peak from 1708 to 1731 cm−1, indicating that an esterification reaction had occurred upon heating, thus producing crosslinked films. Higher molecular weight PEGs (10,000 and 1000 Da, respectively), having greater chain length, producing hydrogel networks with lower crosslink densities and higher average molecular weight between two consecutive crosslinks. Accordingly, such materials exhibited higher swelling rates. Hydrogels crosslinked with a low molecular weight PEG (PEG 200) showed rigid networks with high crosslink densities and, therefore, lower swelling rates. Polymer:plasticizer ratio alteration did not yield any discernable patterns, regardless of the method of analysis. The polymer-water interaction parameter (χ) increased with increases in the crosslink density. SEM studies showed that porosity of the crosslinked films increased with increasing PEG MW, confirming what had been observed with swelling studies and thermal analysis, that the crosslink density must be decreased as the Mw of the crosslinker is increased. Hydrogels containing PMVE/MA/PEG 10,000 could be used for rapid delivery of drug, due to their low crosslink density. Moderately crosslinked PMVE/MA/PEG 1000 hydrogels or highly crosslinked PMVE/MA/PEG 200 systems could then be used in controlling the drug delivery rates. We are currently evaluating these systems, both alone and in combination, for use in sustained release drug delivery devices. 相似文献
6.
Visible-light transparent high-quality substrate-supported poly(2,3-benzofuran) (PBF) film has been successfully electrosynthesized by direct anodic oxidation of 2,3-benzofuran on stainless steel sheet in boron trifluoride diethyl etherate (BFEE) containing 10% poly(ethylene glycol) (PEG) with molar mass of 400 (by volume). The oxidation potential of 2,3-benzofuran in this medium was measured to be only 1.0 V vs. SCE, which is lower than that determined in acetonitrile + 0.1 M Bu4NBF4 (1.2 V vs. SCE). The PBF films obtained in this media showed good electrochemical behaviors and good thermal stability with conductivity of 10−2 S cm−1, and the doping level of as-prepared PBF films was determined to be only 8.9%. The structure and morphology of the polymer were investigated by UV-vis, infrared spectroscopy and scanning electron microscopy (SEM), respectively. To the best of our knowledge, this is the first case for the syntheses of PBF films. 相似文献
7.
A new type of nanocapsules with an oil core, coated by poly(ethylene glycol) (PEG) was designed. The loading efficiency and the biocompatibility of the polymeric nanocapsules were evaluated when it was used as a carrier for hydrophobic agent paclitaxel. The nanocapsules were synthesized through miniemulsion polymerization of butylcyanoacrylate (BCA) with PEG as initiator. The particle size and zeta potential of nanocapsules were influenced by the PEG content in the polymerization system. Fourier transform infrared (FTIR) spectra and 1H NMR demonstrated the chemical coupling between PEG and poly(butylcyanoacrylate) (PBCA). Thermal characteristics of the copolymer were investigated by differential scanning calorimetry (DSC). The encapsulation efficiency increased concurrently with the increase of the PEG content in the system. The hemolytic assay and the cytotoxicity measurement showed that the PEG coating could significantly reduce the hemolytic potential and cytotoxicity of the nanocapsules. The results showed that the PEG-PBCA nanocapsules could be an effective carrier for hydrophobic agents. 相似文献
8.
Prerna Aggarwal Virendra SinghArjun Singh U.W. SchererTejvir Singh Madan L. SinglaAlok Srivastava 《Radiation Physics and Chemistry》2012,81(3):284-289
Thin films of poly(ethyleneterephthalate) (PET) were exposed to different radiation dose brought about by 80 MeV carbon and 98 MeV silicon ion beam. The UV-vis absorption studies reveal that there is decrease in optical band gap energy to the extent of ∼29.3 and 42.1%. The X-ray diffraction analyses have shown that crystallite size decreased by ∼18.6 and 52.6%, indicating amorphization of PET. The colour of PET films change from colourless to light yellowish followed by light brown as radiation dose is increased. The colour formation has been ascribed to an increase in conjugation in the carbon chain. In the case of PET irradiated with carbon ion, the electrical conductivity increased with frequency beyond a threshold value of 1 kHz. The increase in conductivity of PET films on irradiation is due to formation of defects and carbon clusters as a result of polymer chain scission. The thermal study further confirmed the increase in amorphous nature with increase in radiation dose. The results indicate that radiation dose brings about significant physicochemical transformations in PET. 相似文献
9.
PEG作为成孔剂对聚(N-异丙基丙烯酰胺-co-丙烯酸)水凝胶性能的影响 总被引:1,自引:0,他引:1
以PEG400,1000,6000为成孔剂,合成了一系列聚(N-异丙基丙烯酰胺co丙烯酸)水凝胶,研究了成孔剂分子量和数量对凝胶性能的影响.结果表明,聚乙二醇(PEG)分子充当成孔剂,不参与反应.PEG分子量越大,投料越多,所得凝胶孔的孔径越大,孔数目越多,在室温时可以容纳更多的水分子,因而溶胀率也越大.凝胶的大孔结构有利于水分子的进出,所以响应速率比普通共聚凝胶快.随着PEG分子量增大,孔数目增多,响应速率相应变快. 相似文献
10.
A normal-phase HPLC system using an amino column has been developed to characterise oligomers of poly(ethylene glycol)s (PEGs) of average Mr 400 to 2000 with derivatisation by dinitrobenzoate. Normal-phase HPLC with gradient elution using ternary solvents of hexane, dichloromethane and methanol has produced a baseline resolution for oligomers of PEG 400, 600 and 1000, while PEG 1000 and 2000 were analysed by using binary solvents of acetonitrile and water. Mixtures of PEGs have been determined by these HPLC systems. PEG 400 in a textile finish has also been determined with satisfactory recovery. It has been found that the hydroxyl group of solvents in normal-phase HPLC plays an important role in resolution and retention of PEG oligomers. Derivatisation efficiency for PEGs by dinitrobenzoyl chloride and quantitative determination of derivatised PEGs by HPLC have been studied. A reversed-phase (RP) mode of HPLC was examined for determination of PEG 400 oligomers. The normal-phase system provided greater resolution for oligomers of PEGs. 相似文献
11.
Alina Sionkowska 《Polymer Degradation and Stability》2006,91(2):305-312
The photodegradation behaviour of the collagen and poly(ethylene glycol) PEG blends has been studied by Fourier transform infrared spectroscopy (FTIR), UV-Vis spectroscopy and viscometry. Surface properties before and after UV irradiation were observed using optical microscope.Collagen and PEG were immiscible and the films obtained from the mixture were fragile with poor mechanical properties. The photochemical stability of the collagen and PEG blend was different from that of the single components. In general collagen/PEG blends are less stable under UV irradiation than pure collagen. The influence of PEG on the photochemical stability of collagen depends on its concentration in the blend. Microscope photographs showed that the surface characteristics of collagen and collagen/PEG blends in film form are not drastically altered after UV irradiation. 相似文献
12.
13.
Biodegradable multiblock copolymers were synthesized by a polycondensation of poly(ɛ-caprolactone) (PCL) diols of molecular
weight (MW)=3,000 and poly(ethylene glycol)s (PEG) of MW=3,000 with 4,4′-(adipoyldioxy)dicinnamic acid (CAC) dichloride as
a chain extender in diphenyl ether at 180 °C for 2 h, and were characterized by GPC, 1H-NMR, FTIR, UV, DSC, and WAXS. These photosensitive copolymers were irradiated by a 400-W high-pressure mercury lamp (λ>280 nm)
from 5–60 min to form a network structure. The gel contents increased with irradiation time, and attained ca. 90% after 60 min
for all copolymers. The degree of swelling in a distilled water at ambient temperature, and the rate of degradation in a phosphate
buffer solution (pH 7.2) at 37 °C increased with increasing PEG components. The shape-memory tests were performed by a cyclic
thermomechanical experiments for the photocured CAC/PCL/PEG (75/25) films. The film with a gel content of 57% showed the best
shape-memory property with strain fixity rate of 100% and strain recovery rate of 88%. 相似文献
14.
To assess the compatibility of blends of synthetic poly(propylene carbonate) (PPC), with a natural bacterial poly(3-hydroxybutyrate) (PHB), a simple casting procedure of blend was used. poly(3-hydroxybutyrate)/poly(propylene carbonate) blends are found to be incompatible according to DSC and DMA analysis. In order to improve the compatibility and mechanical properties of PHB/PPC blends, poly(vinyl acetate) (PVAc) was added as a compatibilizer. The effects of PVAc on the thermal behavior, morphology, and mechanical properties of 70PHB/30PPC blend were investigated. The results show that the melting point and the crystallization temperature of PHB in blends decrease with the increase of PVAc content in blends, the loss factor changes from two separate peaks of 70PHB/30PPC blend to one peak of 70PHB/30PPC/12PVAc blend. It is also found that adding PVAc into 70PHB/30PPC blend can decrease the size of dispersed phase from morphology analysis. The result of tensile properties shows that PVAc can increase the tensile strength and Young’s modulus of 70PHB/30PPC blend, and both the elongation at break and the tensile toughness increase significantly with PVAc added into 70PHB/30PPC. 相似文献
15.
Thin films of poly(N-vinylcarbazole) (PVK) have been obtained by thermal evaporation under vacuum. The chain length of the polymer is shortened by this deposition technique, which induces a strong reactivity between chlorine and the PVK films. After chlorine doping, there is complex salt formation as shown by electron spin resonance spectroscopy (ESR) and X-ray photoelectron spectroscopy (XPS). However, the major part of the chlorine has reacted with PVK. The thermal evaporation induces amorphization of the PVK, while chlorine doping induces polymer degradation with NH4Cl formation. Because of this degradation the carriers detected by ESR are strongly localized on carbazole radicals, thereby explaining the small increase in the conductivity of PVK films even after chlorine doping. 相似文献
16.
Tsuneo Okubo Tomio Yamada Keisuke Kimura Akira Tsuchida 《Colloid and polymer science》2006,284(4):396-404
Macroscopic and microscopic dissipative structural patterns formed in the course of drying a series of poly (ethylene glycol)
(PEG) having molecular weights ranging from 1,000 to 2×106 in aqueous solution have been studied on a cover glass. The broad ring patterns of the hill accumulated with the polymers
are formed irrespective of the molecular weights of PEG molecules. The single round hills are formed also in the center in
the macroscopic scale, when the molecular weight is large. The characteristic convection flow of the polymers and the interactions
among the polymers and substrate are important for the macroscopic pattern formation. Cross-like fractal patterns are observed,
especially for the diluted solutions in the microscopic scale. These patterns are determined mainly by the electrostatic and
polar interactions between the polymers and/or between the polymer and the substrate in the course of solidification. Interestingly,
these microscopic patterns are reflected based on the shape and size of the PEG polymers. 相似文献
17.
Rheological behaviour of irradiated wound dressing poly(vinyl pyrrolidone) hydrogels 总被引:2,自引:0,他引:2
Ademar B. Lugo Sizue O. Rogero Snia M. Malmonge 《Radiation Physics and Chemistry》2002,63(3-6):543-546
The use of hydrogels as biomaterials has increased lately. Poly(vinyl pyrrolidone) (PVP) is an example of polymer hydrogels applied for the synthesis of hydrogel to be used in different biomedical applications. This paper describes a study on rheological properties of PVP hydrogels obtained by gamma radiation techniques. PVP hydrogels were obtained by gamma radiation of PVP water solutions with different radiation doses. It was studied the influence of additives such as poly(ethylene glycol) (PEG), poly(ethylene oxide) (PEO) and glycerol on the rheological behaviour of the gel. The rheological behaviour of hydrogel samples was characterized by measuring the shear storage modulus (G′) under dynamic shear loading. Besides this, sterility and cytotoxicity tests were performed. The study on rheological behaviour of hydrogels showed that G′ of PVP gels change according to the additive used. Glycerol increases the fluidity of the gel. The influence of PEG depends on the amount and on its molecular mass. The increase on PEG amount and molecular mass cause a decrease of G′ and an increase in the crosslinking density of PVP hydrogel network. The use of high molecular weight PEO allows the increase of the elasticity of the PVP gels. 相似文献
18.
丙烯酰胺在聚乙二醇水溶液中聚合产品的微观形态 总被引:2,自引:0,他引:2
采用偶氮类水溶性引发剂2,2′-偶氮二异丙基咪唑啉二盐酸盐(VA044)引发丙烯酰胺(AM)在聚乙二醇(PEG)水溶液中的双水相聚合;研究了引发剂、单体、聚乙二醇浓度及温度对最终产品中聚丙烯酰胺(PAM)液滴形态、尺寸的影响.随着引发剂浓度的增加,液滴由球状变为细长条状;随着温度的上升,球状液滴逐渐趋于条状,然后又重新趋于球状;在初始单体浓度较低时,PAM液滴滴径分布较窄,当其浓度增加后,滴径呈多峰分布;随着PEG浓度的增加,聚合物液滴趋于球状。 相似文献
19.
Poly(ether sulphone) (PES) is one of the most widely used materials in the micro-electronics industry and a good candidate for the substrates of flexible optoelectronic devices. In this work, the influences of oxygen plasma treatment on the surface chemical composition, surface morphology and optical transparency of PES films were investigated by means of X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and UV-visible spectrophotometry. The possible relations between the optical transparency of the substrate and the surface roughness and chemical composition were also studied. The oxygen plasma treatment seriously changed the surface chemical composition and made the surface more rough. Considerable amounts of sulphate species were found on the plasma-treated surface and the surface roughness values (Ra) increased monotonically with the increase of the treatment time. The PES films treated by 5 min, 15 min, 30 min and 45 min oxygen plasma demonstrated transmission of approximately 98, 94, 68 and 46%, respectively, in the wavelength range of 400-780 nm. The oxygen plasma induced decline of optical transparency of PES films might be attributed to both the increase of surface roughness and the changes of chemical composition of the film surface. 相似文献
20.
Qin Lin Serkan Unal Ann R. Fornof Yuping Wei Huimin Li R. Scott Armentrout Timothy E. Long 《Macromolecular Symposia》2003,199(1):163-172
Linear and branched poly(ethylene terephthalate) (PET) copolymers with polyethylene glycol) (PEG) methyl ether (700 or 2000 g/mol) end groups were synthesized using conventional melt polymerization. DSC analysis demonstrated that low levels of PEG end groups accelerated PET crystallization. The incorporated PEG end groups also decreased the crystallization temperature of PET dramatically, and copolymers with a high content of PEG (>17.6 wt%) were able to crystallize at room temperature. Rheological analysis demonstrated that the presence of PEG end groups effectively decreased the melt viscosities and facilitated melt processing. XPS and ATR-FTIR revealed that the PEG end groups tended to aggregate on the surface, and the surface of compression molded films containing 34.0 wt% PEG were PEG rich (85 wt% PEG). PEG end-capped PET (34.0 wt% PEG) and PET films were immersed into a fibrinogen solution (0.7 mg/mL BSA) for 72 h to investigate the propensity for protein adhesion. XPS demonstrated that the concentration of nitrogen (1.05%) on the surface of PEG endcapped PET film was statistically lower than PET (7.67%). SEM analysis was consistent with XPS results, and revealed the presence of adsorbed protein on the surface of PET films. 相似文献