颗粒表面形貌对电流变液性能影响的机理研究
发布时间：2018-11-13 12:22
【摘要】：电流变液(Electrorheological Fluids,简称ERFs)是一种智能软材料,它通常是由可极化的微纳米尺寸的介电分散相分散在绝缘油中组成的一种智能流体。对其施加电场后,电流变液体系的微观结构和性能会发生明显的变化,因此电流变液被视为具有广泛应用前景的智能材料。纵观电流变液的各个研究阶段可以发现,大多数的研究致力于通过添加极性分子等手段以提高电流变液的剪切屈服强度及稳定性,而关于颗粒形貌对电流变液性能的影响研究甚少,且缺乏相关的机理分析。因此,本文利用溶剂热法制备表面粗糙的花状颗粒,以其为分散相制备电流变液,并与以光滑球形颗粒为分散相的电流变液进行性能对比,来分析颗粒形貌对电流变液剪切屈服强度、沉降稳定性等性能的影响,同时利用摩擦力模型进行粗糙颗粒之间摩擦力对电流变液性能影响的机理研究。研究的主要内容为：(1)将纳米尺度结构和形貌引入微米尺度结构中,利用溶剂热法制备出表面粗糙的花状颗粒和表面光滑的球状颗粒。对花状颗粒和球状颗粒分别进行SEM, TEM, XRD, FT-IR, TGA表征,观察两种颗粒的形貌和尺寸,并对它们的成分进行分析,结果表明两种颗粒均为无定型态。结合两种颗粒的表征分析,进一步推理花状颗粒的形成过程。(2)在静态测试模式下,对比两种颗粒电流变液的电流变性能,研究发现花状颗粒电流变液的电流变性能明显优于球状颗粒电流变液。花状颗粒表面的粗糙形貌有助于提高颗粒与基液的浸润性,增大颗粒间摩擦力,使花状颗粒电流变液获得较高的电流变性能。同时,测试了两种电流变液的沉降稳定性与时间的关系,将它们静置1天后,花状颗粒电流变液的抗沉降率为91.60%,而球状颗粒电流变液的抗沉降率则迅速降至8.49%。花状颗粒表面的刺状结构使其在硅油中不易团聚,并能够获得更大的浮力,所以花状颗粒电流变液的沉降稳定性明显优于以光滑球状颗粒为分散相的电流变液。(3)在动态测试模式下,利用摩擦力模型分析颗粒间摩擦力对电流变液性能的影响。应变与模量变化关系的实验结果表明,在应变为0.1%时两种电流变液都处于各自的线性黏弹区,故后续的动态测试在0.1%应变下进行。对花状颗粒电流变液和球状颗粒电流变液的动态性能进行分析计算可以发现：在低电场强度下,颗粒间摩擦力τf对电流变液的性能起主导作用；在高电场强度下,颗粒间电场力τe对电流变液的性能起主导作用。花状颗粒表面粗糙的刺状结构使其获得了更大的颗粒间摩擦力,从而花状颗粒电流变液具有更好的电流变液性能。因此,颗粒间摩擦力是影响电流变液性能的重要因素。
[Abstract]:Electrorheological fluid (Electrorheological Fluids,) is a kind of intelligent soft material. It is usually a kind of intelligent fluid which is composed of polarizable micro-nanometer size dielectric dispersion phase dispersed in insulating oil. The microstructure and properties of electrorheological fluids will change obviously after applying electric field, so electrorheological fluids are regarded as smart materials with wide application prospects. Looking at the various stages of ER fluids, it can be found that most of the studies focus on increasing the shear yield strength and stability of ER fluids by adding polar molecules. However, the effect of particle morphology on the performance of electrorheological fluids is seldom studied, and there is a lack of relevant mechanism analysis. Therefore, the flower-like particles with rough surface were prepared by solvothermal method, and the electrorheological fluids were prepared by using them as dispersed phase, and compared with those of electrorheological fluids with smooth spherical particles as dispersed phase. The effects of particle morphology on the shear yield strength and settlement stability of ERF were analyzed, and the friction model was used to study the mechanism of the effect of friction between rough particles on ERF performance. The main contents of the study are as follows: (1) Nano-scale structure and morphology are introduced into micron scale structure, and the coarse flower-like particles and smooth spherical particles are prepared by solvothermal method. Flower and spherical particles were characterized by SEM, TEM, XRD, FT-IR, TGA, the morphology and size of the two kinds of particles were observed, and their compositions were analyzed. The results showed that the two kinds of particles were amorphous. Combined with the characterization analysis of two kinds of particles, the formation process of flower-like particles was further deduced. (2) in static test mode, the electrorheological properties of the two kinds of particle electrorheological fluids were compared. It is found that the ER performance of flower-shaped ERF is better than that of spherical ERF. The rough surface morphology of flower-like particles is helpful to improve the wettability of particles and the friction between particles, so that the error-rheological properties of flower-like particles can be improved. At the same time, the relationship between the settling stability and the time of the two electrorheological fluids was tested. After one day of statics, the anti-sedimentation rate of the flower-like ER fluid was 91.60 and that of the spherical ERF decreased rapidly to 8.49g. The spiny structure on the surface of the flower-like particles makes it difficult to reunite in silicone oil and can obtain greater buoyancy. Therefore, the settling stability of error-rheological solution of flower-like particles is obviously better than that of electrorheological fluid with smooth spherical particles as dispersed phase. (3) in dynamic test mode, the effect of friction force between particles on the performance of ERF is analyzed by using friction force model. The experimental results show that the two electrorheological fluids are in their respective linear viscoelastic regions when the strain is 0.1, so the subsequent dynamic tests are carried out at 0.1% strain. Through the analysis and calculation of the dynamic properties of the flower-like particle electrorheological fluid and the spherical particle electrorheological fluid, it can be found that at low electric field strength, the friction between particles 蟿 f plays a leading role in the performance of the ER fluid; At high electric field strength, the interparticle electric field force 蟿 e plays a leading role in the performance of electrorheological fluids. The thorny structure on the surface of flower-like particles makes them obtain greater friction between particles, thus the error-rheological fluids of flower-like particles have better electrorheological properties. Therefore, the friction between particles is an important factor affecting the performance of electrorheological fluids.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB381
[Abstract]:Electrorheological fluid (Electrorheological Fluids,) is a kind of intelligent soft material. It is usually a kind of intelligent fluid which is composed of polarizable micro-nanometer size dielectric dispersion phase dispersed in insulating oil. The microstructure and properties of electrorheological fluids will change obviously after applying electric field, so electrorheological fluids are regarded as smart materials with wide application prospects. Looking at the various stages of ER fluids, it can be found that most of the studies focus on increasing the shear yield strength and stability of ER fluids by adding polar molecules. However, the effect of particle morphology on the performance of electrorheological fluids is seldom studied, and there is a lack of relevant mechanism analysis. Therefore, the flower-like particles with rough surface were prepared by solvothermal method, and the electrorheological fluids were prepared by using them as dispersed phase, and compared with those of electrorheological fluids with smooth spherical particles as dispersed phase. The effects of particle morphology on the shear yield strength and settlement stability of ERF were analyzed, and the friction model was used to study the mechanism of the effect of friction between rough particles on ERF performance. The main contents of the study are as follows: (1) Nano-scale structure and morphology are introduced into micron scale structure, and the coarse flower-like particles and smooth spherical particles are prepared by solvothermal method. Flower and spherical particles were characterized by SEM, TEM, XRD, FT-IR, TGA, the morphology and size of the two kinds of particles were observed, and their compositions were analyzed. The results showed that the two kinds of particles were amorphous. Combined with the characterization analysis of two kinds of particles, the formation process of flower-like particles was further deduced. (2) in static test mode, the electrorheological properties of the two kinds of particle electrorheological fluids were compared. It is found that the ER performance of flower-shaped ERF is better than that of spherical ERF. The rough surface morphology of flower-like particles is helpful to improve the wettability of particles and the friction between particles, so that the error-rheological properties of flower-like particles can be improved. At the same time, the relationship between the settling stability and the time of the two electrorheological fluids was tested. After one day of statics, the anti-sedimentation rate of the flower-like ER fluid was 91.60 and that of the spherical ERF decreased rapidly to 8.49g. The spiny structure on the surface of the flower-like particles makes it difficult to reunite in silicone oil and can obtain greater buoyancy. Therefore, the settling stability of error-rheological solution of flower-like particles is obviously better than that of electrorheological fluid with smooth spherical particles as dispersed phase. (3) in dynamic test mode, the effect of friction force between particles on the performance of ERF is analyzed by using friction force model. The experimental results show that the two electrorheological fluids are in their respective linear viscoelastic regions when the strain is 0.1, so the subsequent dynamic tests are carried out at 0.1% strain. Through the analysis and calculation of the dynamic properties of the flower-like particle electrorheological fluid and the spherical particle electrorheological fluid, it can be found that at low electric field strength, the friction between particles 蟿 f plays a leading role in the performance of the ER fluid; At high electric field strength, the interparticle electric field force 蟿 e plays a leading role in the performance of electrorheological fluids. The thorny structure on the surface of flower-like particles makes them obtain greater friction between particles, thus the error-rheological fluids of flower-like particles have better electrorheological properties. Therefore, the friction between particles is an important factor affecting the performance of electrorheological fluids.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB381
【共引文献】
相关期刊论文 前4条
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