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用AFM研究了PS纳米球在自组装有羧甲基化壳聚糖(CM-CHI)单层膜的云母基底上的吸附行为及CM-CHI自组装膜形貌对PS纳米球吸附行为的影响.重点考察了盐浓度,吸附时间和温度对PS自组装动力学的影响.在CM-CHI自组装膜制备条件一定的情况下,20℃时PS最大覆盖率对应的盐浓度为0.5mol/L,平衡吸附时间为20min,对应的覆盖率约为48.0%.CM-CHI自组装膜形貌对覆盖率的影响主要表现为PS纳米球在由不同方法制备的CM-CHI自组装膜上的覆盖率在最宜吸附盐浓度,平衡吸附时间内随吸附温度的升高而显著增大,当PS吸附温度为60℃时甚至有部分覆盖率达65.0%.此外,还讨论了有关CM-CHI自组装膜是否干燥及PS自组装循环中冲洗用水盐浓度对PS纳米球覆盖率的影响. 相似文献
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采用层层自组装技术与光化学修饰方法相结合在聚氨酯材料表面固定生物多糖衍生物,首先合成具有光反应活性的叠氮壳聚糖,再在聚氨酯基材表面进行叠氮壳聚糖与香菇多糖硫酸酯的层层自组装,然后通过光化学反应对自组装多层膜修饰层进行交联,制备得到生物多糖衍生物层层自组装与光化学表面修饰的聚氨酯材料.通过红外光谱、X射线光电子能谱、水接触角测量仪、抗菌活性测试、溶血试验和血小板黏附测试等方法对被修饰聚氨酯材料的表面性能和生物性能进行了分析,测试结果表明修饰后的聚氨酯材料表面的亲水性和血液相容性得到改善,并且被修饰材料对大肠杆菌具有良好的抑制效果. 相似文献
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磺化聚醚醚酮与壳聚糖共混制备直接甲醇燃料电池用质子交换膜 总被引:1,自引:0,他引:1
给出了不同磺化度下的磺化聚醚醚酮(SPEEK)用作质子交换膜的一系列性能,另外提出了一种新型的酸碱共混质子交换膜,其中,磺化聚醚醚酮和壳聚糖分别被选为酸性、碱性高分子电解质,并对所制备的质子交换膜的相关性能如质子传导性,甲醇渗透性,吸水率以及膜溶胀性、热稳定性等进行了表征,结果表明此种新型复合膜尽管在质子传导性能方面有所下降,阻醇性能改变不大,但是膜溶胀性和吸水率方面有了较大的改善.磺化度为71.4%的SPEEK与壳聚糖以5∶1摩尔比共混制备的质子交换膜,其性质可以与商品化的Nafion 117相媲美,有望在甲醇燃料电池中得到应用. 相似文献
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采用静电吸附层-层自组装方法制备了层状二氧化锰/2,2'-联吡啶铁自组装膜材料,借助扫描电镜(SEM),紫外可见光谱(UV-Vis)和电化学工作站等测试手段对自组装膜的结构与性能进行了表征.结果表明,该自组装膜具有均匀的表面和紧密的层状结构,在可见光照射条件下该自组装膜电极的氧化还原电流明显增加了.层状二氧化锰/2,2'-联吡啶铁自组装膜电极,在可见光照射条件下光电降解有机染料罗丹明B(1×10-5mol/L)反应80min降解率达到了57%. 相似文献
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铝合金表面原位自组装超疏水膜层的制备及耐蚀性能 总被引:3,自引:0,他引:3
采用阳极氧化法在铝合金表面原位构造粗糙结构, 经表面自组装硅氧烷后得到超疏水自清洁表面, 与水滴的接触角最大可达157.5°±2.0°, 接触角滞后小于3°. 通过傅立叶变换红外(FT-IR)光谱分析仪、场发射扫描电子显微镜(FE-SEM)、能谱仪(EDS)、原子力显微镜(AFM)和接触角测试对阳极氧化电流密度、硅氧烷溶液中水的含量和自组装时间等参数进行了分析, 并得到制备超疏水自清洁表面的最优工艺参数. FE-SEM及AFM的测试结果表明, 由自组装硅氧烷膜层的无序性形成的纳米结构和阳极氧化构造的微米级粗糙结构与硅氧烷膜层的低表面能的协同作用构成了稳定的超疏水表面. 电化学测试(动电位极化)的结果表明, 原位自组装超疏水膜层极大地提高了铝合金的耐蚀性. 相似文献
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采用自组装方法将壳聚糖-纳米金(Chi-Nano Au)修饰到金(Au)电极上,并经进一步自组装细胞色素c(Cyt c),制得自组装膜电极Cyt c/Chi-Nano Au/Au.测定了自组装膜电极的循环伏安曲线(CV)及稳定性.结果表明,利用自组装膜电极Chi-Nano Au/Au可以有效地固定Cyt c,并实现直接电子转移反应.Cyt c在0.13~0.28V(vs Ag/AgCl)之间显示一对明显的可逆氧化还原峰;峰电流与扫描速度呈现良好的线性关系,线性方程为Ipc=0.063 64+0.003 51υ,线性相关系数为r=0.997 2,这表明该电极过程受吸附控制.此外,所制备的膜电极稳定性良好. 相似文献
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PEG化壳聚糖/DNA自组装复合物的制备、表征和体外Hela细胞转染研究 总被引:11,自引:0,他引:11
通过有机合成和高分子聚合等方法将亲水性的聚乙二醇接枝到壳聚糖的氨基侧链上,得到了改性的壳聚糖—聚乙二醇接枝共聚物,应用现代波谱等技术对中间产物和最终产物进行了表征,采用绿色荧光蛋白基因质粒pEGFP—N1为DNA模型,在溶液中通过自动(静电)吸附得到PEG化的壳聚糖/DNA自组装复合物,初步研究了该自组装复合物对Hela细胞的体外转染效率。结果表明,活化的聚乙二醇被成功地接枝到壳聚糖上,使不溶于水的壳聚糖改性为水溶性的PEG化的壳聚糖。PEG化壳聚糖/DNA自组装复合物在Hela细胞体外转染率达到81%。因此,PEG化的壳聚糖有可能成为基因转染的非病毒载体。 相似文献
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Mubarak A. Khan Rashidul Alam Farhana G. Noor Ruhul A. Khan Md Arifur Rahman 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(8):751-758
The biodegradable flexible chitosan film was prepared by solution casting. The physico-mechanical properties, polymer loading (PL), gel content and water uptake of the chitosan film were studied. The tensile strength (TS) and % elongation at break (Eb) of the uncured chitosan film were 7.0 (MPa) and 8%, respectively. Four formulations were developed using 3-trimethoxyl silyl propylmethacrylate (TSPMA) (varied from 10–80% by weight) in methanol along with photoinitator (Darocur-1664). The raw chitosan films were then soaked in the prepared formulations and cured under UV radiation at different intensities to improve the physico-mechanical properties of the films. TS for the photocured chitosan film was 28.0 (MPa) which was 4 times higher compared to the uncured chitosan film. This TS was obtained for the formulation containing 30% silane (TSPMA) at 24th UV pass for 4 min soaking time. The maximum PL of 45.1% was obtained for the same formulation at 24th UV pass for 4 min soaking time. The water uptake and gel content of the photocured chitosan films were also studied. The scanning electron micrographs of the photocured chitosan film showed smooth surface, compact and homogeneous structure. 相似文献
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Nusrat Sharmin Ruhul A. Khan Dominic Dussault Stephane Salmieri Nousin Akter Monique Lacroix 《Radiation Physics and Chemistry》2012,81(8):932-935
Chitosan films were prepared by casting from its 1% (w/w) solution. Tensile strength (TS) and tensile modulus (TM) of chitosan films were found to be 30 MPa and 450 MPa, respectively. Silane monomer (3-aminopropyl tri-methoxysilane) (0.25%, w/w) was added into the chitosan solution (1%, w/w) and films were casted. Then films were exposed to gamma radiation (5–25 kGy) and mechanical properties were investigated. It was found that at 10 kGy, the values of TS and TM were improved significantly. Silane grafted chitosan film reinforced poly(caprolactone) (PCL)-based tri-layer composites were prepared by compression molding. Silane improved interfacial adhesion between chitosan and PCL in composites. Surface of the films was investigated by scanning electron microscope (SEM) and found better morphology for silane grafted films. 相似文献
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Cationic wood cellulose films with high strength and bacterial anti-adhesive properties 总被引:1,自引:0,他引:1
Juho Antti Sirviö Anna-Kaisa Anttila Anna Maria Pirttilä Henrikki Liimatainen Ilkka Kilpeläinen Jouko Niinimäki Osmo Hormi 《Cellulose (London, England)》2014,21(5):3573-3583
In this work, periodate oxidized birch wood pulp and microfibrillated cellulose (MFC) were cationized using Girard’s reagent T or aminoguanidine. Cationic celluloses were used to obtain films via solvent-casting method, and the effects of the cationization route and the cellulose fiber source on the properties of the films were studied. Thermal and optical properties of the films were measured using differential scanning calorimetry and UV–Vis spectrometry, and the morphology of the films was examined using an optical microscope and a field emission scanning electron microscope. Bacterial anti-adhesive properties of the films were also studied using a modified leaf print method and against Staphylococcus aureus and Escherichia coli. Both cationizing agents exhibited similar reactivity with periodate oxidized celluloses, however, MFC had significantly higher reactivity compared to birch pulp. The films with high tensile strength (39.1–45.3 MPa) and modulus (3.5–7.3 GPa) were obtained from cationized birch pulp, aminoguanidine modification producing a film with slightly better mechanical properties. Modulus of the films was significantly increased (up to 14.0 GPa) when MFC was used as a cellulose fiber source. Compared to the unmodified MFC films, the cationic MFC films were less porous and significantly more transparent; however, they had slightly lower tensile strength values. It was found that aminoguanidine modified celluloses had no culturable bacteria on its surface and also exhibited resistance to microbial degradation, whereas there were culturable bacteria on the surface of Girard’s reagent modified films and they were partially degraded by the bacteria. 相似文献
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Koev ST Powers MA Yi H Wu LQ Bentley WE Rubloff GW Payne GF Ghodssi R 《Lab on a chip》2007,7(1):103-111
While microcantilevers offer exciting opportunities for mechano-detection, they often suffer from limitations in either sensitivity or selectivity. To address these limitations, we electrodeposited a chitosan film onto a cantilever surface and mechano-transduced detection events through the chitosan network. Our first demonstration was the detection of nucleic acid hybridization. In this instance, we electrodeposited the chitosan film onto the cantilever, biofunctionalized the film with oligonucleotide probe, and detected target DNA hybridization by cantilever bending in solution (static mode) or resonant frequency shifts in air (dynamic mode). In both detection modes, we observed a two-order of magnitude increase in sensitivity compared to values reported in literature for DNA immobilized on self-assembled monolayers. In our second demonstration, we coupled electrochemical and mechanical modes to selectively detect the neurotransmitter dopamine. A chitosan-coated cantilever was biased to electrochemically oxidize dopamine solution. Dopamine's oxidation products react with the chitosan film and create a tensile stress of approximately 1.7 MPa, causing substantial cantilever bending. A control experiment was performed with ascorbic acid solution. It was shown that the electrochemical oxidation of ascorbic acid does not lead to reactions with chitosan and does not change cantilever bending. These results suggest that chitosan can confer increased sensitivity and selectivity to microcantilever sensors. 相似文献
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Henrikki Liimatainen Miikka Visanko Juho Sirviö Osmo Hormi Jouko Niinimäki 《Cellulose (London, England)》2013,20(2):741-749
The consecutive pre-treatment of cellulose with periodate and bisulfite was used as a new potential method to promote nanofibrillation of hardwood pulp and to obtain nanofibrils with sulfonated functionality. Nanofibrils having typical widths of 10–60 nm were obtained from sulfonated celluloses having low anionic charge densities (0.18–0.51 mmol/g) by direct high-pressure homogenization without the use of any mechanical pre-treatments. The aqueous nanofibrils existed as highly viscous and transparent gels and possessed cellulose I crystalline structures with crystallinity indexes of approximately 40 %. A transparent film was obtained from sulfonated nanofibrils having tensile strength of 164 ± 4 MPa and Young’s modulus of 13.5 ± 0.4 MPa. Oxidative sulfonation was shown to be a potential green method to promote nanofibrillation of cellulose, as it avoids the production of halogenated wastes, because the periodate used can be efficiently regenerated and recycled as shown in the preliminary experiments. 相似文献
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《Arabian Journal of Chemistry》2020,13(1):393-403
In this study, novel smart drug release films were prepared by blending chitosan with polyethylene glycol methyl ether (PEGME), also named as methoxy polyethylene glycol (mPEG), for controlled drug release applications. The polymeric films were characterized by Fourier transform infra-red for functional groups analysis, scanning electron microscopy for morphology and X-ray photoelectron spectroscopy for chemical and surface analysis followed by mechanical and thermal analysis. The mechanical properties showed that with the addition of PEGME (40%), the tensile strength and elongation break were increased up to 34.14 MPa and 26.40%, respectively as compared to the controlled sample (without PEGME). The developed biodegradable films were tested for Metformin hydrogen chloride release ability at a particular rate in phosphate buffer saline solution at pH 7.4. The results showed that chitosan/PEGME blends could be employed for controlled drug release and other biomedical applications. 相似文献
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壳聚糖水杨酸盐-明胶共混膜结构表征及其抗菌性 总被引:13,自引:0,他引:13
以溶液共混法成功制备出壳聚糖水杨酸盐-明胶共浊膜,用FT-IR、XRD、SEM表征了其结构,并测试了其吸水率,力学性能及抑菌性能。结果表明,壳聚糖水杨酸盐-胶胶共混膜中存在强烈的氢键相互作用及良好相容性,共混膜的力学性能随明胶含量增大而明显提高,当明胶含量为30%时,共混膜的抗张强度最大,其干、湿态抗张强度分别达99.9MPa和34.9MPa,比纯壳聚糖膜干,湿态抗张强度分别提高了99.8%有83.75,共浊膜抑菌性随明胶含量增加而下降,但其抑菌性仍明显高于壳聚糖膜。水杨酸的引入有利于改善其力学性能及抗菌性能,该共漫漫经膜作为一种潜在的伤口包扎材料,将具有广阔应用前景。 相似文献
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海藻酸钠/羧甲基淀粉共混膜 总被引:6,自引:0,他引:6
用溶液共混法成功制备出海藻酸钠/羧甲基淀粉共混膜,IR、XRD、SEM结构表征以及力学性能、吸水性和水蒸汽透过率测定结果表明:共混膜中海藻酸钠和羧甲基淀粉间存在强烈的分子间氢键等相互作用及良好的相容性;随羧甲基淀粉含量的增加,共混膜的吸水率显著降低;当羧甲基淀粉含量(wCMS)=0.20时,共混膜的抗张强度和断裂伸长率分别为53.1MPa和5.3%,比海藻酸钠膜分别提高了97.4%和60.6%,水蒸汽透过率达最小值,是一种具有潜在应用前景的可食性包装膜材料。 相似文献
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D. L. Morgado E. Frollini A. Castellan D. S. Rosa V. Coma 《Cellulose (London, England)》2011,18(3):699-712
In the present study, films based on linter cellulose and chitosan were prepared using an aqueous solution of sodium hydroxide
(NaOH)/thiourea as the solvent system. The dissolution process of cellulose and chitosan in NaOH/thiourea aqueous solution
was followed by the partial chain depolymerization of both biopolymers, which facilitates their solubilization. Biobased films
with different chitosan/cellulose ratios were then elaborated by a casting method and subsequent solvent evaporation. They
were characterized by X-ray analysis, scanning electron microscopy (SEM), atomic force microscopy (AFM), thermal analysis,
and tests related to tensile strength and biodegradation properties. The SEM images of the biofilms with 50/50 and 60/40 ratio
of chitosan/cellulose showed surfaces more wrinkled than the others. The AFM images indicated that higher the content of chitosan
in the biobased composite film, higher is the average roughness value. It was inferred through thermal analysis that the thermal
stability was affected by the presence of chitosan in the films; the initial temperature of decomposition was shifted to lower
levels in the presence of chitosan. Results from the tests for tensile strength indicated that the blending of cellulose and
chitosan improved the mechanical properties of the films and that an increase in chitosan content led to production of films
with higher tensile strength and percentage of elongation. The degradation study in a simulated soil showed that the higher
the crystallinity, the lower is the biodegradation rate. 相似文献