Fabrication of Macroporous Nafion Membrane from Silica Crystal for Ionic Polymer-Metal Composite Actuator

Xiaojun Zhang,Chengwei Zhang,Minglu Zhang,Man Wang,Manhong Li

doi:10.3390/pr8111389

Abstract

Nafion membrane with macropores is synthesized from silica crystal and composited with Pt nanoparticles to fabricate macroporous ionic polymer-metal composite (M-IPMC) actuator. M-IPMC shows highly dispersed small Pt nanoparticles on the porous walls of Nafion membrane. After the electromechanical performance test, M-IPMC actuator demonstrates a maximum displacement output of 19.8 mm and a maximum blocking force of 8.1 mN, far better than that of IPMC actuator without macroporous structure (9.6 mm and 2.8 mN) at low voltages (5.8–7.0 V). The good electromechanical performance can be attributed to interconnected macropores that can improve the charge transport during the actuation process and can allow the Pt nanoparticles to firmly adsorb, leading to a good electromechanical property.

Highlights

Since Oguro’s group investigated bending behavior under an applied electric field for the first time in 1992, ionic polymer-metal composite (IPMC) is considered as a unique electro-active material [1].Owing to its light weight and large bending deformation under low driving voltage, IPMC has been attracted much attention in smart robot field like artificial muscle [2]
IPMC demonstrate sharper diffraction peaks than macroporous ionic polymer-metal composite (M-IPMC), suggesting that the most of Pt nanoparticles are inserted in the macropores of Nafion membrane
XRD results shows Pt nanoparticles of M-IPMC are small resulting in wide full width at half maximum (FWHM), which has been reported in many literatures [14] in the Figure 2

Summary

Introduction

Since Oguro’s group investigated bending behavior under an applied electric field for the first time in 1992, ionic polymer-metal composite (IPMC) is considered as a unique electro-active material [1].Owing to its light weight and large bending deformation under low driving voltage, IPMC has been attracted much attention in smart robot field like artificial muscle [2]. A typical IPMC actuator is composed of an ion-change polymer membrane (e.g., Nafion or Flemion) and metal (Pt or Au), coated on both sides of the polymer, that are used as working electrodes. The blocking force and displacement are attributed to the migration of cations (normally Li+ ) in the channels of the ion-change membrane. The electrochemical performance of IPMC is depending on various actors, such as the size of metal particles [3], types of polymer [4], and the surface structure of the polymer [5]. Based on above actuation mechanism, the structure of the polymer may play an important role in enhancing the electrochemical performance of IPMC because it can greatly affect the transmission of cations. It is difficult to control the morphology of polymer, and it modifies the surface of the polymer and cannot provide more transport channels for cations

Methods

Results

Conclusion