壳聚糖和木质素磺酸钠膜的电组装制备与应用研究

发布时间：2018-04-23 20:09

本文选题：电组装 + 壳聚糖　；参考：《东华大学》2015年硕士论文

【摘要】：层层自组装作为为数不多能有效地制备纳米材料的方法,近年来一直备受关注。但层层自组装驱动力较弱,制备的自组装膜机械性和实用性较差,根据已有的研究,部分学者提出聚电解质膜是在一个(半)导体的表面形成,因此存在用电势来控制整个组装过程和膜物化性能的可能,并在低电压下进行了尝试。壳聚糖(CS)和木质素磺酸盐(LGS)为天然高分子聚电解质,CS溶液带正电荷,LGS溶液带负电荷,它们具有价格低廉,容易制得,无毒,应用性强等特点,在生物医学、环保、化工等领域都扮演着重要的角色。本论文基于普通静电层层自组装技术,对其进行改进,引入外电场并通过对正负电极的交替联接对组装过程进行调控,制备了CS和LGS的独立电组装薄膜及CS与LGS交替电组装的复合薄膜。采用表面张力仪,接触角,红外光谱,原子力显微镜,扫描电子显微镜,XRD,强度仪对其性能进行表征,而后对CS和LGS独立电组装膜的应用进行研究,分别研究了CS膜的油水分离应用和LGS膜的重金属吸附应用,用紫外吸收光谱对其应用效果进行表征,讨论了优势和不足。以上研究结果如下 (1)通过对CS和LGS溶液的表面张力测试得知,电压对溶液的表面张力有较大的影响。在0-5kV范围内,随着电压的增大,CS和LGS溶液的表面张力都分别降低。这意味着电组装与自组装的主要区别是前者是对低表面张力的高分子溶液进行组装。 (2)电组装膜的表面润湿性研究表明,水的接触角在独立电组装制备的CS和LGS膜表面都是随着电压的增大而减小的。在4kV减弱条件下制备的CS膜的亲水性可以提高1倍以上,而LGS膜则从亲水性转为超亲水性(水接触角为3.910)。而对于(CS/LGS)n复合膜,电压增加将导致其表面疏水性增加,对CS表面而言,4kV范德华力减弱条件将使其表面从亲水性转为疏水性(水接触角为103.90),而对于LGS表面而言,水接触角角将从28.80上升到72.30。 (3)红外光谱研究发现,独立电组装的CS和LGS膜的表面都在制备过程有结构变化。比如,4kV强电压使得CS膜表面露出C-O亲水基团,而LGS膜则露出亲水的磺酸基团。对于(CS/LGS)n复合膜,其表面结构明显改变也是因为电组装所导致的。 (4)根据原子力显微镜和扫描电子显微镜可知,电组装使得所制备的膜的厚度和表面粗糙度都发生变化。 (5)XRD研究发现：电组装的CS膜的结晶度随电压增加而增加。 (6)CS电组装膜的油水分离研究表明其分离效果明显好于普通的CS膜(0电压组装膜)；而LGS电组装膜的重金属吸附研究表面其吸附性能也大大好于普通的LGS膜(0电压组装膜)。
[Abstract]:As one of the few effective methods to prepare nanomaterials, layer-by-layer self-assembly has attracted much attention in recent years. However, the driving force of layer by layer self-assembly is weak, and the mechanical properties and practicability of the self-assembled films are poor. According to the previous studies, some scholars have proposed that the polyelectrolyte film is formed on the surface of a (semi-conductor) conductor. Therefore, it is possible to control the whole assembly process and the physical and chemical properties of the membrane by the potential, and try it at low voltage. Chitosan (CSS) and lignosulfonate (LGSs) are natural polymer polyelectrolytes with positive charge and negative charge in CS solution. They have the characteristics of low price, easy preparation, nontoxic, strong application, etc., in biomedicine, environmental protection, etc. Chemical industry and other fields play an important role. In this paper, based on the conventional electrostatic layer by layer self-assembly technique, the external electric field is introduced and the assembly process is regulated by alternating connection of positive and negative electrodes. CS and LGS self-assembled films and composite films with CS and LGS alternately were prepared. Surface tension instrument, contact angle, infrared spectrum, atomic force microscope, scanning electron microscope (SEM) and intensity meter were used to characterize the properties of the films. The application of CS and LGS films was studied. The application of oil and water separation of CS membrane and heavy metal adsorption of LGS membrane were studied respectively. The application effect was characterized by UV absorption spectrum. The advantages and disadvantages were discussed. The results of the above study are as follows 1) the surface tension of CS and LGS solution is measured and it is found that the voltage has a great influence on the surface tension of the solution. In the range of 0-5kV, the surface tension of CS and LGS solution decreases with the increase of voltage. This means that the main difference between electrical assembly and self-assembly is that the former is a polymer solution with low surface tension. 2) the surface wettability of the electrically assembled film shows that the contact angle of water decreases with the increase of voltage on the surface of CS and LGS films prepared by independent electrical assembly. The hydrophilicity of CS membrane prepared under the condition of 4kV weakening can be increased by more than one fold, while the hydrophilicity of LGS membrane is changed from hydrophilicity to superhydrophilicity (water contact angle is 3.910g). For CS / LGSN composite film, the surface hydrophobicity increases with the increase of voltage. For CS surface, the weakening condition of 4kV van der Waals force will make the surface change from hydrophilicity to hydrophobicity (water contact angle is 103.90), but for the surface of LGS, the hydrophobicity will change to hydrophobicity. The water contact angle will increase from 28.80 to 72.30. The IR spectra show that the surface of CS and LGS films prepared by independent electrical assembly have structural changes during the preparation process. For example, the strong voltage of 4 kV makes C-O hydrophilic group on the surface of CS membrane, while the hydrophilic sulfonic group is exposed on LGS membrane. For CS- / LGSN composite film, the obvious change of surface structure is also caused by electrical assembly. According to atomic force microscope (AFM) and scanning electron microscope (SEM), the thickness and surface roughness of the prepared films are changed by electrical assembly. XRD results show that the crystallinity of electroassembled CS films increases with the increase of voltage. The results of oil-water separation show that the separation effect of the membrane is obviously better than that of the conventional CS film and the adsorption performance of heavy metal on the surface of the LGS film is much better than that of the ordinary LGS film.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.2;O631

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