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Motility of Artificial Muscle using Charge Injection -Solvent Drag by Applying an Electric Field

利用电荷注入-施加电场的溶剂拖曳来实现人造肌肉的运动性

基本信息

批准号：
12450382
负责人：
HIRAI Toshihiro
金额：
$ 4.99万
依托单位：
Shinshu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2003
项目状态：
已结题

项目摘要

The investigations covered wide range of materials from highly swollen polymer gels to non-solvent type of polyurethane elastomers and contained various types of deformations with large strains sometimes exceed 400%, which might be the champion data at this moment.For the actuations of gel materials, there are wide variety of triggers. Polymer gels are defined as polymer materials swollen with large amount of solvent and still hold their shapes with chemical or physical crosslinks among the macromolecule chains. The volume depends mainly on the solvent content in the gel, meaning the swelling and contractile motility can be controlled by the interaction between the solvent and polymer. The interaction between solvent and polymer can be affected by solvent composition, pH, ionic strength, temperature etc., suggesting that the variety of controlling parameter is wide.In these swollen gels, the pressure distribution is uniform in the gels. When we can control pressure distribution in the … More gel, the gel can be deformed without the change in solvent content. To attain the deformation without the volume change, the physical triggers like electric field, magnetic field and light irradiation are convenient. On electric field application, many works have been carried out on polyelectrolyte gels. In the electrical actuation of polyelectrolyte gels, again not only the asymmetric pressure distribution in the gels but also the swelling-and-deswelling migrated in the deforming processes. Moreover, the deforming process accompanies electrochemical reactions on the electrodes, which is an irreversible chemical process or chemical consumption that limit the life span of the materials.To overcome the difficulties of polymer gels as an actuator, I paid attention on non-ionic polymer gels, in which no explicit chemical reaction or consumption could be expected to occur. We found far much quicker response and larger strain compared to the conventional gels. The strain was too large as an electrostatic force and electrical energy dissipation seemed to be very small. In addition to these advantages, the dielectric gels can be actuated in air without the presence of water or aqueous components. Their presence have been known to be inevitable in polyelectrolyte gels or conductive polymer actuators. In the case of poly(vinyl alcohol)(PVA) gel swollen with dimethyl sulphoxide (DMSO), the gel contracts not only in the direction to the electric field, but also can bend by an asymmetric pressure distribution in the gel. The cause of the asymmetric strain in the gel turned out to be charge injection and solvent migration. I call the actuation procedure as "charge-injected-solvent-drag" method. This method can deform the gel laid on an electrode array. The deformation looks like "crawling" worm. The strain can be quantitatively estimated theoretically by the theory of solvent drag. It is interesting to mention that the solvent motion in the gel can be estimated from the solvent migration under the electric field. This analysis suggests that we can estimate the polymer network density by the electrically induced strain.In the case of plasticized poly(vinyl chloride)(PVC), it turned out that the PVC shows "creeping" deformation by applying an electric field. The deformation looks like "pseudoplasmic flow" in amoeba, but it is reversible and restores the original shape as soon as the field is off. We call this deformation as "electrotaxis" in analogy to chemotaxis in biological system. The creep deformation can be applied to joint-like bending deformation. In this case current observed in the deformation is in the range of tens of nA. Bending rate is very swift, and can reach 100 degree in 30 ms, depending on the plasticizer employed. Major difference in this case from PVA-DMSO gel is the absence of the solvent drag, in other words, solvent migration is limited on only the electrode surface accompanying polymer network. Similar deformation could also be successfully induced in other plasticized polymers. For the efficient deformation, it has been elucidated that the electrode asymmetry is critical for the efficient motility.In the elastomer of polyurethane, we investigated it as non-solvent type electroactive actuator, since I can expect the segmented polyurethane elastomer as a kind of plasticized polymer. The difference from plasticized polymer might be the deformability of polymer chains that are strictly restricted by covalent bonding. We expect the physical properties of the elastomer can be controlled as we wish, but so far the most desirable has not been attained yet. Principally, the deformation is suggested to originate from space charge accumulation and its asymmetric distribution. But in the course of searching the electroactive properties of the elastomers, we found strain memory, bending direction control by additives, effect of chemical structures etc. Less

这些研究涵盖了从高度溶胀的聚合物凝胶到非溶剂型聚氨酯弹性体的广泛材料，并包含各种类型的变形，其中大应变有时超过400%，这可能是目前的冠军数据。对于凝胶材料的致动，有各种各样的触发器。高分子凝胶是指在大量溶剂中溶胀后，大分子链间通过化学或物理交联而保持其形状不变的高分子材料。体积主要取决于凝胶中的溶剂含量，这意味着溶胀和收缩运动性可以通过溶剂和聚合物之间的相互作用来控制。溶剂和聚合物之间的相互作用可受溶剂组成、pH、离子强度、温度等影响，在这些溶胀的凝胶中，压力分布是均匀的。当我们可以控制压力分布时， ...更多信息凝胶，凝胶可以变形而不改变溶剂含量。为了获得不改变体积的变形，可以方便地使用电场、磁场和光照射等物理触发。在电场应用方面，人们对电凝胶进行了大量的研究。在电致动的凝胶，再次不仅在凝胶中的不对称的压力分布，而且溶胀和去溶胀迁移的变形过程中。此外，变形过程伴随着电极上的电化学反应，这是一个不可逆的化学过程或化学消耗，限制了材料的使用寿命。为了克服聚合物凝胶作为致动器的困难，我将注意力集中在非离子聚合物凝胶上，其中不可能发生明显的化学反应或化学消耗。我们发现，与传统凝胶相比，反应更快，应变更大。应变太大，因为静电力和电能耗散似乎非常小。除了这些优点之外，介电凝胶还可以在不存在水或水性成分的情况下在空气中激发。已知它们的存在在凝胶或导电聚合物致动器中是不可避免的。在聚乙烯醇（PVA）凝胶用二甲基亚砜（DMSO）溶胀的情况下，凝胶不仅在电场的方向上收缩，而且可以通过凝胶中的不对称压力分布而弯曲。凝胶中的不对称应变的原因原来是电荷注入和溶剂迁移。我称之为“电荷注入溶剂拖动”方法的驱动程序。这种方法可以使放置在电极阵列上的凝胶变形。变形看起来像“爬行”蠕虫。利用溶剂阻力理论可以从理论上定量估算应变。有趣的是，可以从电场下的溶剂迁移来估计凝胶中的溶剂运动。这一分析表明，我们可以通过电致应变来估算聚合物网络密度。在增塑聚氯乙烯（PVC）的情况下，结果表明，通过施加电场，PVC表现出“蠕变”变形。这种变形看起来像变形虫体内的“假浆流”，但它是可逆的，一旦磁场关闭，它就会恢复原来的形状。我们称这种变形为“趋电性”，类似于生物系统中的趋化性。蠕变变形可以应用于关节状弯曲变形。在这种情况下，在变形中观察到的电流在几十nA的范围内。弯曲速度非常快，并且可以在30 ms内达到100度，这取决于所使用的增塑剂。在这种情况下，与PVA-DMSO凝胶的主要区别是不存在溶剂拖曳，换句话说，溶剂迁移仅限于伴随聚合物网络的电极表面上。在其他增塑聚合物中也可以成功地诱导类似的变形。对于有效的变形，它已被阐明，电极的不对称性是关键的有效motility.In聚氨酯弹性体，我们研究了它作为非溶剂型电活性执行器，因为我可以预期的嵌段聚氨酯弹性体作为一种增塑聚合物。与增塑聚合物的不同之处可能是聚合物链的可变形性受到共价键的严格限制。我们期望弹性体的物理性能可以如我们所愿地控制，但到目前为止，最理想的还没有达到。变形主要来源于空间电荷的积累及其不对称分布。但在研究弹性体电活性的过程中，发现了弹性体的应变记忆、添加剂对弯曲方向的控制、化学结构的影响等。