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1.
将聚丙烯腈(PAN)制成纺丝液,加入不同含量的荧光染料罗丹明B(RB),通过静电纺丝的方法,制备荧光纳米纤维,并通过扫描电镜(SEM)观察荧光纳米纤维的表面形态,利用荧光分光光度计表征了纳米纤维的荧光性能。结果表明,不同含量的荧光染料,在相同的纺丝工艺参数下,制备出的荧光纳米纤维具有不同的尺寸及成丝状态,且荧光在一定浓度下强度最高。  相似文献   

2.
对不同浓度活性染料在水溶液中的聚集状态进行了分子动力学模拟研究。通过分析溶液中染料分子的均方根偏差(RMSD)、均方位移(MSD)和溶剂可及表面积(SASA),从宏观上确定染液浓度对染料分子聚集的影响;通过分析溶液中染料分子中C原子的径向分布函数(RDF),定义判断染料分子间发生聚集的通用性标准,进而从微观状态解释造成宏观现象的本质。结果表明:当浓度较低时,染液中染料单体的个数较多,随着染液中染料浓度的增加,染料分子间的聚集程度增大,系统中存在多种聚集体的平衡,但仍有稳定存在的染料单体。染料分子间多以平面堆叠排列的形式存在。  相似文献   

3.
张宾  董霞  何瑾馨 《印染助剂》2013,30(4):16-20,30
用MesoDyn模拟方法,研究了染料聚醚衍生物在水溶液中的聚集行为,讨论了染料聚醚衍生物结构和体积分数对其微相行为的影响.模拟结果表明,不同体积分数下,染料聚醚衍生物可在水溶液中形成3种聚集体:球状胶束、蠕虫状胶束、胶束簇;其胶束形成过程可分为诱导阶段、开始形成阶段、演化阶段和平衡稳定阶段;提高染料聚醚衍生物的初始体积分数可缩短形成胶束的诱导时间,并提高平衡后的有序参数.  相似文献   

4.
为制备低成本可高效电解水的电极,以轻薄柔软的口罩外层聚丙烯无纺布为基底,通过低温溶剂热法(120℃)、电化学沉积两步工艺制备了金属镍电极。研究发现,电极表面均匀且密集地排列了垂直生长的纳米片,比表面积大;在电压为2.1 V和-0.8 V时,电流密度达到了130 mA/cm~2的产氧电流和-130 mA/cm~2的产氢电流,优于泡沫镍和电磁屏蔽布电极;在催化降解罗丹明B印染废水的试验中发现,在1.9 V的电压下,仅需10 min,染料的降解率可达到50%,在75 min内可实现对罗丹明B的完全降解,表现出优异的快速电催化降解能力。  相似文献   

5.
采用荧光倒置显微镜和红外光谱分别考察不同盐浓度、pH值和温度条件下,马铃薯直链淀粉与NaCl溶液作用不同时间的结晶形貌和化学结构变化,初步探索NaCl诱导的马铃薯直链淀粉自聚集行为。结果表明,NaCl溶液浓度为0.1 mol/L时,室温(25℃)下马铃薯直链淀粉分子最易形成结构有序的聚集体。降低温度至4℃,马铃薯直链淀粉分子不易形成结构有序的聚集体。升高NaCl溶液的pH值至弱碱性(pH 8),马铃薯直链淀粉分子更易形成结构有序的聚集体。  相似文献   

6.
在热加工过程中,蛋白易形成聚集体,不同聚集形态蛋白质的界面结构、流变学特性对乳液体系的稳定性及油脂消化特性具有显著影响。为探究β-乳球蛋白聚集体的界面行为,本研究通过调节pH值和加热时间制备了β-乳球蛋白(β-lactoglobulin,β-lg)的不同聚集体,包括β-lg、纳米颗粒聚集体(β-lg NP)和纤维状聚集体(β-lg F),并对这3种形态蛋白质的形貌进行了表征;利用示踪粒子微流变学及膨胀流变学对不同质量分数的β-lg、β-lg NP、β-lg F在油-水(癸烷-水)界面的吸附过程及胆盐取代行为进行研究,并通过体外消化模型实验研究了3种形态蛋白质乳液的消化特性。结果表明,质量分数越高,蛋白向界面扩散越快,形成界面黏弹性越强;蛋白质聚集体比β-lg向界面吸附更快,且形成界面膜弹性更高;在胆盐取代界面蛋白过程中,发现β-lg NP抵抗胆盐取代能力最强,β-lg最弱,与乳液的体外消化模型实验结果一致。  相似文献   

7.
染苑精粹     
《印染》2015,(20)
<正>树状大分子改性萘酰亚胺荧光染料的染色性能2015191采用4-氨基-9-甲基丙醇萘酰亚胺荧光染料(染料1)与聚酰胺-胺型树状大分子(G=-0.5)反应,制备萘酰亚胺-树状分子混合染料(染料2)。通过元素分析、傅里叶转换红外光谱、1H核磁共振光谱和紫外-可见光谱,确定了合成染料的结构;通过测定染料在不同溶剂中的可见光吸收性能,评估了染料的溶剂化显色性能。当溶剂由三氯甲烷换成乙醇,溶剂极性发生改变时,观察到积极的溶剂显  相似文献   

8.
以三氟乙酸(TFA)为溶剂,纺制了壳聚糖(CS)、柞蚕丝素/壳聚糖(TSF/CS)纳米纤维,并用甲醇、乙醇处理纳米纤维,观察其微观形态的改变。先配制不同质量分数的CS溶液,通过静电纺丝技术纺制CS纳米纤维,用扫描电镜(SEM)对样品进行形貌观察和分析,在本试验条件下获得形貌良好的CS纳米纤维的最佳溶解时间为1~1.5 d,最佳质量CS分数为2%。以TFA为溶剂,将溶解1.5 d的10%TSF溶液和2%CS溶液按一定的配比混合,通过静电纺丝技术纺制/CS复合纳米纤维,当混合比2∶2时,纤维形态外观最佳。经过甲醇和乙醇处理后,纳米纤维出现不同程度的粘连。研究结果可为生物医学材料和组织工程支架提供理论支持。  相似文献   

9.
董文丽  徐刚 《食品与机械》2015,31(2):122-124,133
研究Fe3+与过量KI反应生成I3-对罗丹明B荧光信号的猝灭作用。在盐酸介质中,Fe3+与过量KI反应生成I3-,I3-与罗丹明B形成离子缔合物,猝灭罗丹明B分子的内源性荧光,使其荧光强度显著降低。据此,建立Fe(Ⅲ)—KI—RB体系间接测定铁的荧光分析方法。体系的最大激发波长和最大发射波长分别为352 nm和580 nm,铁(Ⅲ)含量在0.02~4.50μg/25 m L范围内与罗丹明B荧光猝灭值ΔF呈良好的线性关系,方法的检出限为0.006μg/25 m L,用该法测定花生中微量铁,相对标准偏差小于2%,加标回收率在96.7%~101.0%,结果满意。  相似文献   

10.
以活性橙13为研究对象,采用UV/Vis分光光度法探讨染料浓度、介质温度、pH及电解质对染液可见光吸收性能的影响,并测定了相应条件下染料颗粒的粒径,据此推测染料在不同状态下聚集状态的变化。研究表明,高浓度条件下,染料溶液的λmax发生红移,伴随染料颗粒粒径增大,表明染料分子逐渐形成不同的聚集体;升高介质温度或pH值时,高浓度染液的λmax呈蓝移,染料颗粒直径呈减小趋势,表明升温或提高pH值可使聚集体大幅度解聚,但前者并不能使染料聚集体完全解聚;而电解质的加入则会加剧高浓度染液的聚集情况,且不同金属离子(K+,Na+,Li+)因金属离子半径不同,对染液聚集的影响程度为K+>Na+>Li+。  相似文献   

11.
Amyloid β protein (Aβ) from Alzheimer's disease formed fibrillar aggregates and their morphology depended on oxidized and negatively charged liposomes. The morphology of fibrillar aggregates was affected by Cu2+, together with their growth kinetics. This is because Cu2+ inhibited the nucleation step in the formation of amyloid Aβ fibrillar aggregates by forming Aβ/Cu complex inactive to the growth of fibrillar aggregates. In addition, this is probably because Cu2+ affected the fibrillar aggregate formed on the surface of liposomes. These findings would give a better understanding of the formation mechanism of amyloid fibrils on biomembranes.  相似文献   

12.
The hierarchical ordering at micro- and nano-scales in hybrid composites of alginate and silica nanoparticles was observed when uniform microparticles were formed in a single step via a micro-fluidic jet spray drying. A polymer-mediated ‘bricks and mortar’ strategy initially aligned silica nanoparticles into nano-clusters in the dispersion with sizes depending on the ratio of polymer to silica. Evaporation induced self-assembly during spray drying then formed uniform microparticles with shells enriched with silica nanoparticles, enclosing arrays of close-packed spherical aggregates of these nano-clusters. The final structures of particles were determined by the drying temperature and the ratio of alginate to silica, indicating that this approach could be used to fabricate diverse structural motifs. The combination of polymer-mediated self-assembly with a moderate temperature spray drying could be a versatile route to synthesize thermal sensitive, ordered biomaterials for food and pharmaceutical-related applications.  相似文献   

13.
本研究采用分子自组装技术制备虾青素/乳清蛋白纳米复合物,并探究虾青素(Astaxanthin,AST)与乳清蛋白(Whey Protein)之间的分子相互作用机制。选用乳清蛋白(α-乳白蛋白、β-乳球蛋白、浓缩乳清蛋白、牛血清蛋白)与虾青素自组装,通过控制水相蛋白质溶液与有机相虾青素溶液的比例,分别可控形成H聚集体或J聚集体虾青素/乳清蛋白纳米复合物(H/J Aggregates Astaxanthin/Whey Protein Nanocomplexes)。通过动态光散射仪(Dynamic Light Scattering,DLS)测定虾青素/乳清蛋白纳米复合物的粒径均在150~430 nm之间,多分散性指数(Polydispersity Index,PDI)表明分散性良好,电位在?12~?1 mV之间;采用透射电子显微镜(Transmission Electron Microscope,TEM)观察成功制备出的H聚集体或J聚集体虾青素/乳清蛋白纳米复合物呈边缘清晰光滑的近球形结构;紫外可见光谱表明4种蛋白质构建的H聚集体或J聚集体虾青素/乳清蛋白纳米复合物中虾青素H聚集体最大吸收波长λmax由虾青素单体的λmax480 nm蓝移至388 nm,虾青素J聚集体最大吸收波长λmax光谱红移,并显示出519和556 nm左右的并肩峰;通过荧光光谱分析表明由于虾青素聚集体特定的结构使形成的虾青素/乳清蛋白纳米复合物的荧光强度都明显增强,乳清蛋白中疏水性氨基酸及疏水性区域暴露。本研究从虾青素及其聚集体的水分散性和乳清蛋白载体特性两方面探究,为其后续在食品药品领域的开发及应用提供理论依据。  相似文献   

14.
Thermal association-dissociation behavior of soybean 11S globulin was investigated by sucrose density gradient centrifugation and polyacrylamide gel electrophoresis. Soluble aggregates with a molecular weight of 8 × 106 were formed when 0.5% and 5% protein solutions were heated for 1 min at 100°C. At the lower protein concentration, subsequent heating caused disappearance of the soluble aggregate followed by complete dissociation into acidic and basic subunits. At the higher concentration, however, subsequent heating caused formation of highly polymerized aggregates, and gel was formed after 5 min of heating. The soluble aggregates appear to be transient intermediates in the course of gel formation of 11S globulin.  相似文献   

15.
为了明确蛋白质的纤维聚集行为,本研究以大豆球蛋白(soy globulin,11S)为原料,从亚基层面对酸性条件下热诱导的11S纤维聚集过程进行跟踪,监测蛋白及其亚基的水解过程、结构变化及其稳定性。结果表明,11S的纤维化是一个多步骤的过程,包括多肽链的水解、自组装成淀粉样纤维聚集结构及逐渐生长成宏观可见的具有扭曲螺旋结构的纤维聚集体。与11S纤维化过程的单指数增长相比,酸性亚基的纤维化过程存在迟滞期。酸性亚基在纤维化聚集的初期主要贡献于纤维聚集的成核过程,碱性亚基的加入改变其纤维聚集进程。蛋白质的纤维化过程会增加11S在等电点处的溶解度,降低中性和酸性pH下的溶解度。此外,碱性环境(pH值10.0)会导致11S纤维聚集体全部溶解、宏观纤维长度变小、结构发生改变。以上研究结果旨在为合理利用蛋白纤维化聚集体作为新的功能性食品配料提供理论依据。  相似文献   

16.
黄娟  杨宇  于海燕  陈臣  田怀香 《食品科学》2023,44(3):258-268
环糊精因具有独特的“外亲水、内疏水”结构,可作为一种优良的包合载体对性质活泼、易挥发、易氧化分解的活性组分进行保护,从而达到提高其溶解度、稳定性和生物利用率的效果。本文从环糊精的结构与性质出发,首先对其包合机理进行探究,即分析主体环糊精与客体分子之间的相互作用和影响因素,包括环糊精单体与客体之间的包合反应、环糊精单体之间的自组装行为以及该行为下所形成的超分子体系与客体分子的包合机制;接着阐述有无表面活性剂存在的情况下环糊精界面稳定机制、表面活性剂与环糊精自组装形成复合乳化剂协同稳定客体机制等;然后,对环糊精包合物中客体分子的释放机制、缓释动力学模型及相应的影响因素进行解析;最后,从分子模拟及界面稳定机制方面对环糊精在超分子领域的研究进行展望,以期为后续研究提供参考。  相似文献   

17.
The assembly behavior of biopolymers is affected by the type of solvent used. Previous investigations have focused on the self-assembly of zein molecules in aqueous ethanol. In this study, the self-assembly behavior of zein molecules in aqueous acetic acid solutions and their application in the development of zein-based gluten-free doughs was investigated. Zein molecules in low concentrations of acetic acid (30%–60%, v/v) assembled into irregular entities, in medium concentrations (70%, v/v) there was intermediate transition, and at high concentrations (80%–100%, v/v) they formed regular spheres. Interestingly, protein fibril formation was found to occur in 50% zein solutions in 50% and 60% acetic acid, as self-standing gels with solid-like properties resulted and the findings were verified using rheology. The 50% zein solutions in 70% acetic acid could form viscoelastic masses after anti-precipitation with the addition of excess water. Gluten-free dough with wheat-like properties was obtained by mixing the viscoelastic zein masses with wheat starch at room temperature. SEM observations showed that the formation mechanism for zein-based doughs involves the dispersion of starch granules in a three-dimensional zein network. These results will help to improve our understanding of zein assembly behavior regulation, and provide technical support for the development of zein in gluten-free food products.  相似文献   

18.
Recent interest is focused on microcapsules stabilized using colloidal nanoparticles – termed ‘colloidosomes – for encapsulation applications in food, drug and cosmetic industries. However, due to electrostatic repulsion between similarly charged particles, shells composed of single-type nanoparticles tend to be monolayer-thick and relatively permeable. We investigated a self-assembly method for controlling the permeability of colloidal shells using aggregates composed of oppositely charged silica nanoparticles. Using a combination of rapid fluorescence based method and theoretical diffusion models, we found that colloidosomes whose shells contained colloidal silica aggregates displayed lower permeability to peroxyl radicals than ones stabilized by single type of silica nanoparticles. Furthermore, the permeability varied as a function of the ratio of oppositely charged silica nanoparticles in the shell. The ability to control the permeability of colloidosomes, while using a simple self-assembly synthesis method, will enable enhanced control over release kinetics and oxidative stability of encapsulants.  相似文献   

19.
《Food Hydrocolloids》2007,21(5-6):896-905
Phosvitin is an egg yolk protein constituted by 50% of serines which are all phosphorylated. Because of this peculiarity, phosvitin has a high charge density and is known to be one of the most natural cation-binding proteins. In addition, phosvitin naturally forms aggregates through phosphocalcic bridges in egg yolk. This high charge density, doubled by this capacity to aggregate, limits the adsorption of the protein at oil–water or air–water interfaces. In this work, we investigated the impact of both the charge, by sodium chloride (NaCl) addition, and the aggregation, by calcium chloride addition, on the interfacial properties of phosvitin. The air–water interfacial activity of the phosvitin was studied with a Wilhelmy-type film balance and a Brewster angle microscope. In the presence of increasing NaCl concentrations, phosvitin presents improved interfacial properties and the film formed was more dense. The better adsorption of the phosvitin is attributed to the charge screening due to NaCl which could permit a higher spreading of the protein at the interface. Concerning the aggregation effect, calcium–phosvitin aggregates favour the contact between the protein and the interface and act on the interfacial film morphology inducing the formation of a thicker and a more rigid interfacial phosvitin film.  相似文献   

20.
We investigated the phase diagrams and the morphology of the complexes that were formed by cationic polymers, cationic cellulose (CC) and cationic dextran (CD), and by anionic surfactant‐based sodium poly(oxyethylene) lauryl ether sulfate (LES). The anionic charge of the LES‐based surfactants was changed by adding an amphoteric surfactant, lauryl amidopropyl betaine acetate (LPB), or a nonionic surfactant, polyoxyethylene stearyl ether (C18EO25). We discuss the relationship between the complex aggregation process and the morphology of the precipitated complexes. The morphologies of CC complex aggregates, which precipitated during the dilution process in a model shampoo solution, changed from membranous forms to mesh‐like forms by decreasing the charges of both the CC and the surfactant. Their touch on hair in the rinsing process changed from sticky to smooth and velvety, corresponding to their rheological properties. In contrast, CD complex aggregates had a membranous form and a smooth touch independently of the charges on the polymer and surfactant. These results suggested that the control of the charges of both the polymer and surfactant and the choice of polymer structure are important for excellent conditioning effects upon rinsing with shampoo.  相似文献   

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