scholarly journals Molecular dynamics of ionic polymer-metal composites

Author(s):  
A. Truszkowska ◽  
M. Porfiri

Ionic polymer-metal composites (IPMCs) constitute a promising class of soft, active materials with potentially ubiquitous use in science and engineering. Realizing the full potential of IPMCs calls for a deeper understanding of the mechanisms underpinning their most intriguing characteristics: the ability to deform under an electric field and the generation of a voltage upon mechanical deformation. These behaviours are tightly linked to physical phenomena at the level of atoms, including rearrangements of ions and molecules, along with the formation of sub-nanometre thick double layers on the surface of the metal electrodes. Several continuum theories have been developed to describe these phenomena, but their experimental and theoretical validation remains incomplete. IPMC modelling at the atomistic scale could beget valuable support for these efforts, by affording granular analysis of individual atoms. Here, we present a simplified atomistic model of IPMCs based on classical molecular dynamics. The three-dimensional IPMC membrane is constrained by two smooth walls, a simplified analogue of metal electrodes, impermeable only to counterions. The electric field is applied as an additional force acting on all the atoms. We demonstrate the feasibility of simulating counterions’ migration and pile-up upon the application of an electric field, similar to experimental observations. By analysing the spatial configuration of atoms and stress distribution, we identify two mechanisms for stress generation. The presented model offers new insight into the physical underpinnings of actuation and sensing in IPMCs. This article is part of the theme issue ‘Progress in mesoscale methods for fluid dynamics simulation’.

2019 ◽  
Vol 23 ◽  
pp. 64-74
Author(s):  
Ponnusamy Senthil Kumar ◽  
P.R. Yaashikaa

Electroactive polymers, or EAPs, are polymers that show an adjustment fit as a fiddle when invigorated by an electric field. Ionic polymer metal composites (IPMCs) are electro-dynamic polymers with great electromechanical coupling properties. They are proficient applicants in many progressed innovative applications, for example, actuators, artificial muscles, biomimetic sensors, and so forth. Type of membrane and electrodes determines the morphology and structure of IPMCs. IPMCs can be prepared using physical loading, chemical deposition and electroplating methods. The assembling of anodes for IPMCs is exceptionally basic in their electromechanical coupling. Optimization of force, determination of cations and molecule size dispersal inside the IPMC structure, and so on are the different components, which decides their proficiency. An ionic polymer-metal composite (IPMC) comprising of a thin Nafion sheet, platinum plated on the two side faces, experiences extensive twisting movement when an electric field is connected over its thickness. Then again, a voltage is created over its appearances when it is all of a sudden bends. IPMCs are best known for their proving advantages such as biocompactible, low activating voltage and more power efficiency


Author(s):  
J. Paquette ◽  
K. J. Kim ◽  
J.-D. Nam ◽  
Y. S. Tak

Ionic Polymer-Metal Composite (IPMC) is a new class of polymeric material exhibiting large strain with inherent soft actuation. The observed motion characteristics of an IPMC subjected to an electric field is highly non-linear. This is believed to be due primarily to the particle electrodes on the IPMC surface, which is inherently both capacitive and resistive due to particle separation and density. Knowing that the value of resistivity and capacity can be manipulated by the number of metal platings applied to the IPMC, the force response of an IPMC when subjected to an imposed electric field is due to the interaction of an array of capacitors and resistors along with ionic migration. In this effort we attempt to incorporate a capacitive and resistive model into the previously developed linear irreversible thermodynamic model. The advantages of using such a model are i) the possible dynamic predictability of the material itself; and ii) the realization of capacitive and resistive effect arising from the particle electrodes and the base polymer, respectively. The behavior of the proposed model can explain typical experimentally obtained values well. Also, an experimental effort to improve the properties of the base polymer was carried out by a novel nanocomposite technique. The experiment results on the current/voltage (I/V) curves indicate that the starting material of ionic polymer-metal composites (IPMCs) can be optimized to create effective polymer actuators.


2013 ◽  
Vol 389 ◽  
pp. 298-303 ◽  
Author(s):  
Muhammad Farid ◽  
Zhao Gang ◽  
Yu Min Zhu ◽  
Ashleigh Chatto ◽  
Raja Ahsan Javed

This paper presents an overview of ionic polymer metal composites (IPMC), various properties improving techniques employed in the last decade and its potential applications. IPMC consists of a polymer membrane sandwiched by metal electrodes. On application of a small voltage, it bends towards anode. Due to its low activation voltage requirement (1-3V), low weight, high flexibility and ability to take any shape, IPMC has attracted the attention of researchers whose current aim include enhancing the force output to make them applicable for use in industrial, underwater SONARS, energy harvesting and biomedical fields. This paper provides an overview of the efforts made by the research community over the last decade, the identified applications with the references for elaborated study.


2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Alain Boldini ◽  
Maxwell Rosen ◽  
Youngsu Cha ◽  
Maurizio Porfiri

Abstract A recent experiment by Kim’s group from the University of Nevada, Las Vegas, has shown the possibility of actuating ionomer cilia in salt solution. When these actuators are placed between two external electrodes, across which a small voltage is applied, they move toward the cathode. This is in stark contrast with ionic polymer metal composites, where the same ionomers are plated by metal electrodes but bending occurs toward the anode. Here, we seek to unravel the factors underlying the motion of ionomer cilia in salt solution through a physically based model of actuation. In our model, electrochemistry is described through the Poisson–Nernst–Planck system in terms of concentrations of cations and anions and voltage. Through finite element analysis, we establish that Maxwell stress is the main driving force for the motion of the cilia. This study constitutes a first effort toward understanding the motion of ionomer cilia in salt solution, which, in turn, may help elucidate the physical underpinnings of actuation in ionic polymer metal composites.


2009 ◽  
Vol 419-420 ◽  
pp. 785-788
Author(s):  
Xiu Fen Ye ◽  
Yu Dong Su ◽  
Shu Xiang Guo

An Ionic polymer metal composites (IPMC) actuated 3D swimming microrobot is presented first. Inspired by biologic fins, passive plastic fin is attached to the IPMC strip to increase the thrust. Infrared sensors are equipped for wireless control and autonomous navigation. Then propulsive efficiency analyses are carried out. From the water electrolysis influence analysis of the IPMC, the best working voltage is confirmed. Finally, a two parts IPMC actuator is presented to improve the propulsive efficiency of the microrobot after the analysis of propulsive efficiency of caudal fin.


Author(s):  
Muhammad Farid ◽  
Zhao Gang ◽  
Tran Linh Khuong ◽  
Zhuang Zhi Sun ◽  
Naveed Ur Rehman ◽  
...  

Biomimetic is the field of engineering in which biological creatures and their functions are investigated and are used as the basis for the design and manufacturing of machines. Ionic Polymer Metal Composite (IPMC) is a smart material which has demonstrated a meaningful bending and tip force after the application of a low voltage. It is light-weighted, flexible, easily actuated, multi-directional applicable and requires simple manufacturing. Resultantly, IPMC has attracted scientists and researchers to analyze it further and consider it for any industrial and biomimetic applications. Presently, the research on IPMC is bi-directional oriented. A few groups of researchers are busy to find out the causes for the weaknesses of the material and to find out any remedy for them. The second class of scientists is exploring new areas of applications where IPMC material can be used. Although, the application zone of IPMC is ranging from micropumps diaphragms to surgical holding devices, this paper provides an overview of the IPMC application in biomimetic and biomedical field.


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