Please cite this article in press as: V. Panwar, et al., High actuation response of PVDF/PVP/PSSA based ionic polymer metal composites actuator, Sens. Actuators B: Chem. (2011), doi:10.1016/j.snb.2011.10.062 ARTICLE IN PRESS G Model SNB-13553; No. of Pages 11 Sensors and Actuators B xxx (2011) xxx–xxx Contents lists available at SciVerse ScienceDirect Sensors and Actuators B: Chemical journa l h o mepage: www.elsevier.com/locate/snb High actuation response of PVDF/PVP/PSSA based ionic polymer metal composites actuator Varij Panwar, Kyoungrae Cha, Jong-Oh Park ∗ , Sukho Park ∗ School of Mechanical Systems Engineering, Chonnam National University, Gwangju 500-757, Republic of Korea a r t i c l e i n f o Article history: Received 10 August 2011 Received in revised form 18 October 2011 Accepted 25 October 2011 Available online xxx Key words: Ionic polymer Actuator Ionic polymer metal composites Actuation response Proton conductivity a b s t r a c t For the biomedical application of IPMC actuator, IPMC should generate fast and large tip displacement at low direct current (DC) and alternating current (AC) voltages of 1–2 V. In this paper, the tip displacement of polyvinylidene fluoride (PVDF)/polyvinyl pyrrolidone (PVP)/polystyrene sulfonic acid (PSSA) based ionic polymer metal composites (IPMCs) actuators were tested at DC and AC voltages of 1–2 V, and the results were compared with that of the Nafion based IPMC actuator. Research on the PVDF/PVP/PSSA ionic membrane identified two novel compositions of PVDF/PVP/PSSA of blend ratios of 25/15/60 and 30/15/55 for the IPMC actuator which gave higher ion exchange capacity (IEC) and higher water uptake (WUP) than that of the Nafion membrane and proton conductivity nearly equal to that of the Nafion membrane. In an ionic membrane, PVDF is the hydrophobic polymer, PVP the basic, water-soluble polymer, and PSSA the strong, water-soluble polyelectrolyte, which provides the free charge carrier. A high-performance ionic polymer actuator should have large IEC, large WUP and large proton conductivity. At DC and AC voltages of 1–2 V, the PVDF/PVP/PSSA based actuator showed larger actuation with quick response time than those of the Nafion based IPMC actuator. The capacitance and imaginary part of impedance of all IPMCs were calculated at AC voltages of 1–2 V and the actuation performances of IPMCs were also tested and compared. © 2011 Elsevier B.V. All rights reserved. 1. Introduction IPMCs [1–8], which belong to the ionic electroactive polymers (EAPs) category, can be used as biomimetic sensors and actua- tors in medical devices [9,10], engineering devices and robotics applications. The other ionic EAP polymers are polymer gels [11], conducting polymers [12] and carbon nanotubes [13]. IPMC exhibits a large bending displacement at a low applied voltage. An IPMC consists of an ionic membrane sandwiched between two noble metal plates [4]. When voltage is applied to a water-saturated cantilevered strip of IPMC in an alkali-metal cation form, the cations along with water molecules move from one electrode surface to the other electrode surface in ion-water clusters, bending the IPMC; this bending is called actuation. The most common ionic polymer membrane used in the fab- rication of IPMCs is the perfluorinated polymer membrane, e.g. the Nafion series from DuPont (USA). This membrane consists of a large hydrophobic fluorocarbon backbone and short hydrophilic sulfonic pendant side chains. The hydrophobic fluorocarbon back- bone of the membrane governs the mechanical strength of the ∗ Corresponding authors. E-mail addresses: jop@jnu.ac.kr (J.-O. Park), spark@jnu.ac.kr (S. Park). membrane and the short hydrophilic sulfonic pendant side (SO 3 −1 H + ) chains provide the ionic groups that interact with water and control the passage of appropriate ions [2,3]. When the ionic polymer is hydrated, the cations (H + or Li + ) associated with the SO 3 −1 groups become mobile, allowing the polymer to conduct cations while anions (negatively charged ions) are fixed to the ionic polymer membrane. Therefore, conduction in ionic polymer mem- brane is possible due to the cations in hydrated state. The Nafion is fluorinated polymer, which is less environmentally friendly, and its cost is too high for practical applications [14]. Although Nafion- based IPMC actuators have shown good actuation performance, they have problems such as the straightening-back phenomenon under a DC electric field [4–6]. Therefore, over the past few years, some research group has proposed a cheaper and ecologically more acceptable ionic polymer membrane to replace the most widely used Nafion family polymer actuators [6,8,15–17]. Recently, we analyzed the actuation PVDF/PVP/PSSA based actu- ators at DC voltages of 2.5 and 3 V and reported that IPMCs based on PVDF/PVP/PSSA ionic membranes of blend ratios of 60/20/20 and 50/25/25 depicted slow and small actuation below the DC voltage of 2.5 V possibly due to low proton conductivity [18]. The proton conductivities of PVDF/PVP/PSSA ionic membranes of blend ratios of 60/20/20 and 50/25/25 were 0.01 and 0.02, respectively. After further research on this material, we found new compositions of 0925-4005/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.snb.2011.10.062