绕曲形微纤维和银纳米粒子链的可控制备

发布时间：2018-07-25 19:26

【摘要】：柔性或可拉伸性光电子器件是未来电子器件的发展趋势,它能被拉伸、弯曲和扭曲至一定形变,柔性或可拉伸性导体是它的重要组成部分,“结构可拉伸”是制备可拉伸导体的一大策略。具有绕曲形(波浪形或三维螺旋形)结构的导电材料在受张力时能被拉伸至一定应变而属于可拉伸性导体。基于静电纺丝中射流力学弯曲可制备绕曲形纤维,该法简单而有效且成本低。然而静电纺丝中有关绕曲形纤维的形成条件和制备机理鲜有报道。本学位论文主要基于静电纺丝法可控制备了具有绕曲形结构(波浪形或三维螺旋形)聚合物纤维,所制备的绕曲形聚合物纤维有望用于制备可拉伸性导体。结合静电纺丝法和煅烧制备了银纳米粒子链网络,探索其制备条件和形成机理,所制备的银纳米粒子链网络具有局域等离子共振效应而有望应用于柔性传感器上。具体研究内容及结论如下:(1)以聚苯乙烯/二甲基甲酰胺溶液为例,研究了波浪形纤维在静电纺丝中的形成过程和制备原理,探索了波浪形纤维的振幅随静电纺丝参数的变化规律,并制备了不同类型的波浪形纤维阵列。研究发现,随着收集板速度的增加,聚合物纤维的形貌沿着线圈形、“W”形、波浪形和直线形的规律变化。对波浪形纤维振幅随收集板速度的变化进行分析,发现直线形纤维与波浪形纤维之间的转变属于Hopf分岔,即由垂直于收集板移动方向上的非线性扰动产生具有O(2)对称性的Hopf分岔,导致波浪形纤维的产生。波浪形纤维与“W”形纤维的转变可能来源于纤维横向和纵向运动模式的改变。波浪形纤维振幅的极大值出现在波浪形与“W”形纤维转变处,且该振幅极大值随着纺丝电压和针头-收集板间距的增加而增大;波浪形与“W”形纤维的临界转变速度随纺丝电压的增加而增加,但该临界速度受针头-收集板间距的影响不大。(2)基于以液体为接收端的静电纺丝法,制备了形貌规则可控的三维螺旋聚苯乙烯微纤维,研究了三维螺旋聚苯乙烯纤维的形成条件,探索了影响线径和外径的影响因素。此外,为了验证本章中制备的三维螺旋纤维在柔性电子器件方面的应用前景,模拟了空心银弹簧在受到拉力时的长度变化以及应力分布,探讨了其与弹性聚合物基体的力学匹配性。研究发现,直射流和较高的针头移动速度(40 mm/s)是获得形貌规则三维螺旋的必要条件。随着纺丝针头-液面间距的增大,三维螺旋的外径和直径逐渐增大。低浓度的聚合物溶液有利于降低三维螺旋的线径和外径。此外,有限元力学模拟显示,与上述三维螺旋尺寸相当的空心银弹簧在受到拉伸外力时,能够获得53%的弹性形变率,且其形变行为与弹性聚合物基体如聚二甲基硅氧烷(PDMS)匹配。(3)以AgNO3/聚乙烯吡咯烷酮(PVP)溶胶为研究体系,提出了一种不需要预先合成银纳米粒子且高效简便的银纳米粒子链网络制备方法。基于静电纺丝-煅烧法,探索了静电纺丝制备AgNO3/PVP纳米复合纤维的条件,研究了纳米复合纤维煅烧过程中的温度对银纳米粒子产物排列及银纳米粒子尺寸的影响规律。研究发现当AgNO3与PVP的体积比为2:5时,能制备无珠粒且表面光滑的纳米复合纤维。煅烧温度较低时(500 oC)银纳米粒子呈链状排列且平均直径小于150 nm,而当煅烧温度较高时(850 oC)银纳米粒子呈无序排列且粒子直径主要分布于500~700 nm。对纳米粒子链网络的紫外-可见光谱分析,所制备的银纳米粒子链网络在362 nm和506 nm处出现吸收峰,这有利于其在与表面等离子共振相关的领域中应用。
[Abstract]:Flexible or extensible optoelectronic devices are the development trend of electronic devices in the future. It can be stretched, bent, and twisted to a certain deformation. Flexible or extensible conductors are important parts of it. "Structure extensible" is a major strategy for the preparation of extensible conductors. The material can be stretched to a certain strain when tension is stretched and it belongs to the extensible conductor. Based on the mechanical bending of the jet mechanics in the electrostatic spinning, the winding fiber can be prepared. This method is simple and effective and has low cost. However, there are few reports on the forming conditions and preparation mechanism of the winding fibers in the electrostatic spinning. This dissertation is mainly based on the electrostatic spinning method. It is possible to control the preparation of a polymer fiber with a winding structure (wavy or three-dimensional spiral). The prepared winding polymer fiber is expected to be used for the preparation of extensible conductors. A silver nanoparticle chain network is prepared by electrostatic spinning and calcining. The preparation conditions and formation mechanism of the silver nanoparticles are explored. The silver nanoparticle chain network is prepared. The local plasma resonance effect is expected to be applied to flexible sensors. The specific contents and conclusions are as follows: (1) the forming process and preparation principle of wavy fiber in electrostatic spinning are studied with polystyrene / two methyl formamide solution as an example. The variation of the amplitude of wavy fiber with the parameters of electrostatic spinning is explored, and the system is made. It is found that with the increase of the velocity of the collection plate, the morphology of the polymer fiber changes along the shape of the coil, "W" shape, the wave shape and the straight line. The change of the amplitude of the wavy fiber along with the velocity of the collection plate is analyzed, and the transformation of the linear fiber to the wavy fiber is found. Hopf bifurcation, from the nonlinear disturbance perpendicular to the moving direction of the collection plate, produces a Hopf bifurcation with O (2) symmetry, resulting in the formation of a wavy fiber. The transformation of the wavy fiber and the "W" fiber may come from the change of the transverse and longitudinal motion patterns of the fiber. The maximum amplitude of the wavy fiber appears in the wave shape and "W" "Shape fiber transition, and the maximum amplitude of the amplitude increases with the increase of the spinning voltage and the spacing of the needle collector plate; the critical speed of the wave and the" W "fiber increases with the increase of the spinning voltage, but the critical velocity is not affected by the spacing of the needle collector plate. (2) the electrostatic spinning method based on the liquid as the receiving end is made. The three-dimensional spiral polystyrene Microfiber with controllable morphology is prepared. The forming conditions of the three-dimensional spiral polystyrene fiber are studied, and the influence factors of the diameter and diameter are explored. In addition, in order to verify the application prospect of the three-dimensional spiral fiber in this chapter, the hollow silver spring is simulated by the tension. It is found that the direct flow and higher needle moving velocity (40 mm/s) are necessary conditions for obtaining the three-dimensional spiral of regular morphology. With the increase of the distance between the needle and the liquid surface of the spinning needle, the outer diameter and diameter of the three dimensional helix gradually increases. The polymer solution is beneficial to reduce the line diameter and the outer diameter of the three dimensional spiral. In addition, the finite element mechanical simulation shows that the elastic deformation rate of the hollow silver spring equivalent to the above three dimensional spiral size can be obtained by 53%, and the deformation behavior is matched with the elastic polymer matrix, such as poly (PDMS). (3) AgNO3/ Polyvinylpyrrolidone (PVP) sol was used as a study system. A new method of preparation of silver nanoparticles chain network was proposed without pre synthesis of silver nanoparticles. Based on the electrostatic spinning and calcining method, the conditions for the preparation of AgNO3/PVP nanocomposite fibers by electrostatic spinning were explored. The temperature of the calcining process of the nano composite fibers was studied. The influence of the particle size of silver nanoparticles and the size of silver nanoparticles was studied. It was found that when the volume ratio of AgNO3 and PVP was 2:5, the nanoscale composite fibers with no bead and smooth surface could be prepared. The silver nanoparticles were arranged in chain and the average diameter was less than 150 nm when the calcined temperature was low, while the calcined temperature was higher (850 oC) when the calcined temperature was higher. The nanoparticles are arranged in a disordered arrangement and the particle diameter is mainly distributed in the ultraviolet visible spectrum analysis of the nanoparticle chain network by 500~700 nm.. The silver nanoparticles chain network has the absorption peak at 362 nm and 506 nm, which is beneficial to its application in the field related to the surface plasmon resonance.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ340.64;TB383.1

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