几种纸浆纤维表面的原子力显微镜分析

利用原子力显微镜(AFM)对几种较具代表性的纸浆纤维表面进行了分析。分析结果表明,棉纤维及桦木KP、桉木CTMP、云杉TMP等纤维在表面形貌及表面化学组成上存在较大区别,这是造成这些纤维的结合力以及纤维与化学添加剂之间结合能力各不相同的重要原因。     

枸杞多糖对HepG2细胞膜表面超微结构变化的影响

目的:研究枸杞多糖对人肝癌HepG2细胞膜表面超微超微结构变化的影响。方法:利用倒置显微镜和原子力显微镜观察不同浓度(0、50、100、200、400μg/mL)和不同作用时间下(24h、48h)枸杞多糖对HepG2细胞膜表面结构变化的影响。结果:随作用时间和多糖浓度的增加,细胞膜表面形态发生了明显的变化,膜表面结构由光滑变得粗糙,细胞膜表面粗糙度由1.451nm变到295.977nm,部分形成孔洞和隆起,表面结构遭到了明显的破坏。结论:枸杞多糖能破坏HepG2细胞膜结构,这可能与枸杞多糖的抗肿瘤作用有关。     

丙纶表面沉积纳米薄膜的原子力显微镜分析

采用低温磁控溅射技术在丙纶(熔喷法非织造布)表面沉积铝、氧化锌和聚四氟乙烯纳米薄膜,用原子力显微镜观察纤维基材及三种纳米薄膜沉积在纤维表面的微观结构,为进一步对聚合物纤维材料磁控溅射功能化加工的工艺参数优化调整,以及对沉积材料在纤维表面的结合机理的研究提供理论依据。通过对原子力显微镜图像分析发现,丙纶(熔喷法非织造布)表面比较平滑,而丙纶长丝的表面则成一定的周期性条纹状结构;低温磁控溅射技术在丙纶(熔喷法非织造布)表面构建的功能性纳米薄膜随着沉积材料的不同,其在纤维表面的聚集形态不同。铝和氧化锌在纤维表面形成纳米颗粒状结构,而高分子材料聚四氟乙烯则形成纳米条带状形貌。分析和测量了金属颗粒和聚四氟乙烯条带的尺寸。     

CLSM技术在纤维表面形态和纸张结构研究中的应用

采用共聚焦激光扫描显微镜(CLSM),可以在不损伤样品的前提下获得样品的三维图像,具有较高的横向(XY向)分辨率和信噪比。综述了CLSM的工作原理,重点讨论了其在纤维表面分析(纤维形态和表面的木素)、纤维形变性研究(柔韧性和压溃性能)以及纸张结构观察(表面结构和内部结构)中的应用。     

纤维的表面性能及表面分析技术

阐述了纤维表面性能的重要性,并主要介绍了扫描电镜(SEM)、透射电镜(TEM)、原子力显微镜(AFM)、激光共聚焦扫描显微镜(CLSM)、X射线光电子能谱(XPS)、二次离子质谱(SIMS)等现代表面分析技术及其在制浆造纸研究中的应用.     

纸浆纤维表面特性与表面化学成分的研究方法和研究进展

该文以表面分析技术为出发点,阐述了纸浆纤维表面性能的重要性,并通过介绍主要的表面分析技术,如原子力显微镜(AFM)、激光共聚焦扫描显微镜(CLSM)、二次离子质谱(SIMS)等现代表面分析技术及其在制浆造纸领域中的应用,综合论述了纸浆纤维的表面特性和表面化学成分的研究方法和研究进展。     

AFM和XPS结合在化学浆和机械浆纤维表面分析中的应用

较全面地介绍了原子力显微镜(AFM)与化学分析电子能谱(xPs)结合用于化学浆和机械浆纤维表面分析的情况.分析表明.组成纤维表面的多种物质之间的吸引和排斥作用导致纤维表面的多孔性.关于AFM图像纤维表面的球状颗粒幸i7=和片状结构的解释存在着很大的不同,AFM相图中明暗对照的解释,以及明暗对照与纤维表面的亲水件、疏水性和软硬黏弹性之间的关系尚没有明确的解释.     

纳米微晶纤维素的阳离子表面功能化

纳米微晶纤维素由硫酸水解棉花得到,它同环氧丙基三甲基氯化铵(EPTMAC)经过一系列的反应表面变得阳离子化。生成的纳米微晶悬浮液的特点是ζ电位、电导滴定法、显微镜偏正光、原子力显微镜(AFM)显示改性后的纳米微晶体的尺寸和形状无变化,但是功能化过程转变其表面电荷,并导致总表面电荷密度的减少。这个改性引起稳定的纤维纳米晶体水悬浮液不希望的凝胶及流变特性。横波双折射,却无法检测到分离的液晶手性向列相。简介控制酸水解纤维素悬浮物得到的棒状、高结晶度的纤维素纳米粒子,其性能同时受纤维素本身和水解条件的影响。     

非木材化学浆表面超微结构的AFM观察

利用原子力显微镜(AFM)研究了几种非木材化学浆DQP漂白前后纤维表面超微结构的变化.经过DQP漂白,几种非木材化学浆的白度达到80%以上,脱木素率均超过88%,漂白对几种非木材化学浆的强度有一定的提高,但作用效果因原料种类而异.利用AFM对纸浆纤维表面进行观察,结果表明,漂白前覆盖存纤维表面的颗粒状物质经过漂白后溶出,反映了表面木素的脱除.另外,大量微细纤维暴露出来,图像的相差降低,反映了漂白后纤维表面的亲水性和均一性得到提高,即漂白后纸浆表面性质得到改善,这可能是纸浆强度提高的原因.     

塑料薄膜基上镀纳米SiOx涂层的表征及性能研究

本文利用等离子体气相化学沉积(PECVD)的方法,在聚对苯二甲酸乙二醇酯(PET)和双向拉伸聚丙烯(BOPP)薄膜上制备了纳米厚度的SiOx涂层。使用傅里叶变换红外光谱(FTIR)、原子力显微镜(AFM)和超声原子力显微镜(UAFM)对纳米厚度的SiOx薄膜进行表征。利用AFM和UAFM,可以得到SiOx薄膜的形貌和超声幅值成像。尤其是本文使用的新方法UAFM,可以表征表面和次表面缺陷。同时,本文实验研究了,镀SiOx的PET和BOPP薄膜的拉伸性能、接触角和阻隔性。结果表明,SiOx涂层提高了塑料薄膜的阻隔性、拉伸性能。     

Storage induced changes to high protein powders: influence on surface properties and solubility

BACKGROUND: MPC 80 is a high‐protein (80%) milk powder commonly used in the food industry as a functional ingredient and valued for its nutritional quality. However, its rehydration properties decline during storage, causing more time to be required for rehydration of the powder by the end user. It is thought that changes at the surface of the powder particles contribute to this reduced solubility during storage. RESULTS: Surface composition and structural changes in milk protein concentrate (MPC) were observed during 90 days of storage at temperatures of 25 and 40 °C and relative humidities of 44, 66 and 84%. No significant changes to the surface composition (fat, protein and lactose) of the MPC powder samples occurred during storage; however, some changes in the microstructure of the powders were observed. Scanning electron microscopy analysis of the powder particles during dissolution showed the formation of a crust, consisting of a thin layer of fused casein micelles, on the surface of the stored powders. An increase in the hydrophobicity at the surface of the particles was evident by X‐ray photoelectron spectroscopy analysis of the bonding state of the elements at or near the surface and by atomic force microscopy measurements of the adherence of particles to the surface of a material. CONCLUSION: The development of this ‘crust’ is thought to contribute to the decrease in the solubility of the powder particles during storage. The increase in the hydrophobicity at the surface and the casein micelle interactions resulting in the surface crust formation appear to contribute to the decrease in the solubility of MPC during storage. Copyright © 2011 Society of Chemical Industry     

Application of atomic force microscopy as a nanotechnology tool in food science

Atomic force microscopy (AFM) provides a method for detecting nanoscale structural information. First, this review explains the fundamentals of AFM, including principle, manipulation, and analysis. Applications of AFM are then reported in food science and technology research, including qualitative macromolecule and polymer imaging, complicated or quantitative structure analysis, molecular interaction, molecular manipulation, surface topography, and nanofood characterization. The results suggested that AFM could bring insightful knowledge on food properties, and the AFM analysis could be used to illustrate some mechanisms of property changes during processing and storage. However, the current difficulty in applying AFM to food research is lacking appropriate methodology for different food systems. Better understanding of AFM technology and developing corresponding methodology for complicated food systems would lead to a more in-depth understanding of food properties at macromolecular levels and enlarge their applications. The AFM results could greatly improve the food processing and storage technologies.     

现代仪器分析技术在黄酒分析研究中的应用

介绍了光谱、色谱等分析法中几种现代仪器分析技术的基本原理及其在黄酒分析研究中的应用,总结了目前黄酒研究中常用的分析方法。     

原子力显微镜在淀粉颗粒结构研究中的应用

本文首先介绍了原子力显微镜的基本原理，硬件结构和工作模式，其次将原子力显微镜在淀粉颗粒结构研究中的应用做了一个简要的综述。利用原子力显微镜观察淀粉颗粒表面和内部的精细结构，对比较不同植物学来源的淀粉和在淀粉颗粒结构上考察基因突变对淀粉的影响，以及在淀粉糊化或贮藏的回生阶段追踪淀粉颗粒结构的变化都具有十分重要的辅助意义。     

纳米氧化镁对活性炭纤维表面的修饰

通过化学沉积法将纳米MgO微粒分散在活性炭纤维表面。分析了NaOH浓度及反应时间对活性炭纤维负载MgO的影响,得出了在活性炭纤维表面负载均匀的纳米MgO颗粒的最佳条件。利用扫描电子显微镜(SEM)观察到分散在活性炭纤维表面的MgO颗粒直径在50~100 nm之间;用X射线光电子能谱(XPS)对活性炭纤维表面进行分析,结果也表明在纤维表面存在MgO微粒。     

Influence of chemical treatment on tensile strength,water absorption,surface morphology,and thermal analysis of areca sheath fibers

Proper surface modification is highly essential to improve compatibility of natural fibers with polymer matrix to develop eco-friendly materials. In the present work, an attempt has been made to study the effect of various chemical treatments such as alkaline, acrylic acid, permanganate, sodium chlorite, and benzoylation on areca sheath fiber. After surface modifications, its density, water absorption property, mechanical property, thermal gravimetry analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and surface morphology have been thoroughly investigated. It has been observed that benzoyl chloride-treated fiber gives better performance in comparison to other treatments.     

XPS、AFM和ToF-SIMS的工作原理及在植物纤维表面分析中的应用

介绍了先进的表面分析仪器化学分析电子能谱(XPS)、原子力显微镜(AFM)、含飞行时间分析器的二次离子质谱仪(ToF-SIMS)的工作原理,回顾了近年来它们在植物纤维表面分析中的成功应用,综合利用XPS、AFM及ToF-SIMS方法,可分析和解决制浆造纸过程中的现象和问题。     

膳食纤维分析方法研究进展

膳食纤维作为一种来源丰富的功能性食品原料,具有重要的生理功能——能够降低便秘、结肠癌、肥胖、心血管疾病、糖尿病等慢性病的发病率。文中就膳食纤维分析方法的研究进展进行了综述,介绍了传统的分析方法,以及近红外分析法、尺寸排阻液相色谱法、高效阴离子色谱法等现代仪器分析方法。     

Membrane fouling during filtration of milk––a microstructural study

The surface morphology and internal microstructure of a membrane are the result of membrane manufacturing processes and subsequent use during fluid processing in industry. Both these structural factors have a great effect on fouling and filtration performance.

In this study, scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy were used to comprehensively characterise the surface of unused microfiltration and ultrafiltration membranes, the fouled layer on the surface of membranes used for milk filtration and the internal fouling within the used membranes.

A simple and effective sample preparation method was developed to study the internal membrane structure using high-resolution field emission SEM with low-accelerating voltage. Various methods of structural characterisation were compared and the results showed that for flat sheet membranes AFM is an appropriate and convenient technique for examining the surface topography of membranes. In contrast SEM is a very appropriate technique for examining the cross-sectional and internal structure of a membrane, either unused or fouled.

Using these complimentary techniques it has been shown that internal fouling, during filtration of skim milk, proceeds by protein–polymer and protein–protein interactions. A gel layer forms on the surface of the membrane and has been imaged using SEM. This layer is slightly compressible and densifies as it grows. Fouling initiation commences after a very short filtration time.     

Advances in research on structural characterisation of agricultural products using atomic force microscopy

Atomic force microscopy (AFM) has many unique features compared with other conventional microscopies, such as high magnification with high resolution, minimal sample preparation, acquiring 2D and 3D images at the same time, observing ongoing processes directly, the possibility of manipulating macromolecules, etc. As a nanotechnology tool, AFM has been used to investigate the nanostructure of materials in many fields. This mini-review focuses mainly on its latest application to characterise the macromolecular nanostructure and surface topography of agricultural products. First the fundamentals of AFM are briefly explained. Then the macromolecular nanostructure information on agricultural products from AFM images is introduced by exploring the structure-function relationship in three aspects: agricultural product processing, agricultural product ripening and storage, and genetic and environmental factors. The surface topography characterisation of agricultural products using AFM is also discussed. The results reveal that AFM could be a powerful nanotechnology tool to acquire a deeper understanding of the mechanisms of structure and quality variations of agricultural products, which could be instructive in improving processing and storage technologies, and AFM is also helpful to reveal the essential nature of a product at nanoscale.