Elisabeth Smela, Professor, Mechanical Engineering, University of Maryland

CP References

This page is under construction. References are more or less complete from 2004 through 2007.

If you find this list useful for a publication, please cite it in the Acknowledgments, for example with, "We acknowledge E. Smela's web site for providing a valuable list of references on the topic of conjugated polymer actuators."

Polymer Code:	PPy = polypyrrole PANI = polyaniline PEDOT = poly(3,4-ethylenedioxythiophene) PTh = polythiophene several = several different CPs
Topic Code:	device = actuator demonstration ion = ion transport study or drug release material = new material mechanism = actuation mechanism study	micro-act = micro-scale actuator model = actuation model performance = performance measurement review = review article

Click on column headers to sort by that column: i.e., click Year to sort by year.

Year	Polymer	Topic	First Author	Corresponding Author	Paper
2009	PPy	ion	Wang	Smela	X. Wang and E. Smela Color and volume change in PPy(DBS) J. Phys. Chem. C, 113 (1), 359-368, 2009

2008	PPy	other	Prakash	Abshire	S. B. Prakash, M. Urdaneta, M. Christophersen, E. Smela, and P. Abshire In situ electrochemical control of electroactive polymer films on a CMOS chip Sens. Act. B, 129 (2), 699-704, 2008
2008	PPy	performance	Chu	Travas-Sejdic	S. Y. Chu, H. Peng, P. A. Kilmartin, G. A. Bowmaker, R. P. Cooney, and J. Travas-Sejdic Effect of deposition current density on the linear actuation behaviour of PPy(CF3SO3) films Curr. Appl. Phys., 8 (3-4), 324-327, 2008

2007	PPy	performance	Alici	Alici	G. Alici and N. N. Huynh Performance quantification of conducting polymer actuators for real applications: A microgripping system IEEE/ASME Trans. Mechatronics, 12 (1), 73-84, 2007
2007	PPy	device	Alici	Spinks	G. Alici, G. Spinks, N. N. Huynh, L. Sarmadi, and R. Minato Establishment of a biomimetic device based on tri-layer polymer actuators-propulsion fins Bioinsp. Biomim., 2, S18-S30, 2007
2007	PPy	performance	Fujisue	Kaneto	H. Fujisue, T. Sendai, K. Yamato, W. Takashima, and K. Kaneto Work behaviors of artificial muscle based on cation driven polypyrrole Bioinsp. Biomim., 2, S1-S5, 2007
2007	PPy	device	He	Shi	X. M. He, C. Li, F. E. Chen, and G. Q. Shi Polypyrrole microtubule actuators for seizing and transferring microparticles Adv. Funct. Mater., 17 (15), 2911-2917, 2007
2007	PPy	performance	Kaneto	Kaneto	K. Kaneto, H. Fujisue, M. Kunifusa, and W. Takashima Conducting polymer soft actuators based on polypyrrole films - energy conversion efficiency Smart Mater. Struct., 16 (2), S250-S255, 2007
2007	PPy	device	Kiefer	Travas-Sejdic	R. Kiefer, S. Y. Chu, P. A. Kilmartin, G. A. Bowmaker, R. P. Cooney, and J. Travas-Sejdic Mixed-ion linear actuation behaviour of polypyrrole Electrochim. Acta, 52 (7), 2386-2391, 2007
2007	PPy	other	Kim	Martin	D. H. Kim, S. M. Richardson-Burns, J. L. Hendricks, C. Sequera, and D. C. Martin Effect of immobilized nerve growth factor on conductive polymers: Electrical properties and cellular response Adv. Funct. Mater., 17 (1), 79-86, 2007
2007	PPy	other	Liu	Smela	Y. Liu, Q. Gan, S. Baig, and E. Smela Improving PPy adhesion by surface roughening J. Phys. Chem. C, 111 (30), 11329-11338, 2007
2007	PPy	performance	Madden	Madden	J. D. Madden, D. Rinderknecht, P. A. Anquetil, and I. W. Hunter Creep and cycle life in polypyrrole actuators Sens. Act. A, 133 (1), 210-217, 2007
2007	PPy	micro-act	Madou	Madou	M. Madou and H.-K. A. Tsai Microfabrication of bilayer polymer actuator valves for controlled drug delivery J. Assoc. Lab. Auto., 12 (5), 291-295, 2007
2007	PPy	performance	Otero	Otero	T. F. Otero, J. J. L. Cascales, and G. V. Arenas Mechanical characterization of free-standing polypyrrole film Mat. Sci. Eng. C, 27 (1), 18-22, 2007
2007	PPy	material	Preethichandra	Kaneto	D. M. G. Preethichandra, A. K. Thakur, W. Takashima, and K. Kaneto A combined bi-ionic polymer actuator with unidirectional extension against bipolar excitations Sens. Act. B, 122 (2), 587-590, 2007
2007	PPy	device	Sutar	Yakhmi	D. Sutar, D. K. Aswal, S. K. Gupta, and J. V. Yakhmi Electrochemical actuator from conductive electroactive polymer polypyrrole deposited on gold Indian J. Pure Appl. Phys., 45 (4), 354-357, 2007
2007	PPy	force	Takashima	Kaneto	W. Takashima, K. Hayasi, and K. Kaneto Force detection with Donnan equilibrium in polypyrrole film Electrochem. Commun., 9, 2056-2061, 2007
2007	PPy	device	Tangorra	Hunter	J. Tangorra, P. Anquetil, T. Fofonoff, A. Chen, M. Del Zio, and I. Hunter The application of conducting polymers to a biorobotic fin propulsor Bioinsp. Biomim., 2 (S6-S47), 2007
2007	PPy	micro-act	Tsai	Madou	H. K. A. Tsai, K. S. Ma, C. Wang, H. Xu, C. L. Wang, J. Zoval, L. Kulinsky, and M. Madou Development of integrated protection for a miniaturized drug delivery system Smart Mater. Struct., 16 (2), S295-S299, 2007
2007	PANi	material	Spinks	Spinks	G. M. Spinks, S. R. Shin, G. G. Wallace, P. G. Whitten, I. Y. Kim, S. I. Kim, and S. J. Kim A novel "dual mode" actuation in chitosan/polyaniline/carbon nanotube fibers Sens. Act. B, 121 (2), 616-621, 2007
					top of page
2006	PPy	model	Alici	Huynh	G. Alici and N. N. Huynh Predicting force output of trilayer polymer actuators Sens. Act. A, 132 (2), 616-625, 2006
2006	PPy	model	Alici	Spinks	G. Alici, P. Metz, and G. M. Spinks A methodology towards geometry optimization of high performance polypyrrole (PPy) actuators Smart Mater. Struct., 15 (2), 243-252, 2006
2006	PPy	model	Alici	Cook	G. Alici, B. Mui, and C. Cook Bending modeling and its experimental verification for conducting polymer actuators dedicated to manipulation applications< Sens. Act. A, 126 (2), 396-404, 2006
2006	PPy	material	Hara	Kaneto	S. Hara, T. Zama, W. Takashima, and K. Kaneto Tris(trifluoromethylsulfonyl)methide-doped polypyrrole as a conducting polymer actuator with large electrochemical strain Synth. Met., 156 (2-4), 351-355, 2006
2006	PPy	performance	Otero	Otero	T. F. Otero, G. V. Arenas, and J. J. L. Cascales Effect of the doping ion on the electrical response of a free-standing polypyrrole strip subjected to different preloads: Perspectives and limitations associated with the use of these devices as actuators Macromol., 39 (26), 9551-9556, 2006
2006	PPy	model	Otero	Otero	T. F. Otero and I. Boyano Characterization of polypyrrole degradation by the conformational relaxation model Electrochim. Acta, 51 (28), 6238-6242, 2006
2006	PPy	device	Otero	Otero	T. F. Otero and M. Broschart Polypyrrole artificial muscles: a new rhombic element. Construction and electrochemomechanical characterization J. Appl. Electrochem., 36 (2), 205-214, 2006
2006	PPy	material	Pytel	Hunter	R. Pytel, E. Thomas, and I. Hunter Anisotropy of electroactive strain in highly stretched polypyrrole actuators Chem. Mater., 18 (4), 861-863, 2006
2006	PPy	material	Tanaka	Kaneto	A. Tanaka, W. Takashima, and K. Kaneto Improved cathodic expansions of polypyrrole films by poly(2-methoxyaniline-5-sulfonate) incorporation Thin Solid Films, 499 (1-2), 179-184, 2006
2006	PPy	performance	Wu	Wallace	Y. Wu, G. Alici, G. M. Spinks, and G. G. Wallace Fast trilayer polypyrrole bending actuators for high speed applications Synth. Met., 156 (16-17), 1017-1022, 2006
2006	PPy	micro-act	Xu	Madou	H. Xu, C. Wang, C. L. Wang, J. Zoval, and M. Madou Polymer actuator valves toward controlled drug delivery application Biosens. Bioelectron., 21 (11), 2094-2099, 2006
2006	PPy	performance	Zama	Kaneto	T. Zama, N. Tanaka, W. Takashima, and K. Kaneto Fast and large stretching bis(trifluoromethylsulfonyl)imide (TFSI)-doped polypyrrole actuators and their applications to small devices Polymer J., 38 (7), 669-677, 2006
2006	PEDOT	ion	Abidian	Martin	M. R. Abidian, D.-H. Kim, and D. C. Martin Conducting-polymer nanotubes for controlled drug release Adv. Mater., 18, 405-409, 2006
2006	PEDOT	material	Vidal	Chevrot	F. Vidal, C. Plesse, H. Randriamahazaka, D. Teyssie, and C. Chevrot Long-life air working semi-IPN/ionic liquid: New precursor of artificial muscles Molec. Cryst. Liq. Cryst., 448, 95-102, 2006
2006	PT	performance	Xi	Wallace	B. Xi, V.-T. Truong, P. Whitten, J. Ding, G. M. Spinks, and G. G. Wallace Poly(3-methylthiophene) electrochemical actuators showing increased strain and work per cycle at higher operating stresses Polymer, 47 (22), 7720-7725, 2006
					top of page
2005	PPy	device	Dennler	Reiss	J. Causley, S. Stitzel, S. Brady, D. Diamond, and G. Wallace Electrochemically-induced fluid movement using polypyrrole Synth. Met., 151 (1), 60-64, 2005
2005	PPy	device	Dennler	Reiss	G. Dennler, N. S. Sariciftci, R. Schwodiauer, S. Bauer, and H. Reiss Electromechanical strain in conjugated polymer diodes under forward and reverse bias Appl. Phys. Lett., 86 (19), 2005
2005	PPy	material	Hara	Kaneto	S. Hara, T. Zama, W. Takashima, and K. Kaneto Free-standing gel-like polypyrrole actuators doped with bis(perfluoroalkylsulfonyl)imide exhibiting extremely large strain Smart Mater. Struct., 14 (6), 1501-1510, 2005
2005	PPy	material	Hara	Kaneto	S. Hara, T. Zama, W. Takashima, and K. Kaneto Free-standing polypyrrole actuators with response rate of 10.8% s(-1) Synth. Met., 149 (2-3), 199-201 2005
2005	PPy	device	Hara	Kaneto	S. Hara, T. Zama, N. Tanaka, W. Takashima, and K. Kaneto Artificial fibular muscles with 20% strain based on polypyrrole-metal coil composites Chem. Lett., 34 (6), 784-785, 2005
2005	PPy	material	He	Shi	X. He and G. Shi Electrochemical actuator based on monolithic polypyrrole-TiO2 nanoparticle composite film Sens. Act. B, 115 (1), 488-493, 2005
2005	PPy	material	Lu	Mattes	W. Lu, I. D. Norris, and B. R. Mattes Electrochemical actuator devices based on polyaniline yarns and ionic liquid electrolytes Aust. J. Chem., 58, 263-269, 2005
2005	PPy	material	Nakashima	Kaneto	T. Nakashima, D. Kumar, W. Takashima, T. Zama, S. Hara, S. Sewa, and K. Kaneto Enhanced electrochemical strain in polypyrrole films Curr. Appl. Phys., 5 (2), 202-208, 2005
2005	PPy	material	Onoda	Tada	M. Onoda, H. Shonaka, and K. Tada A self-organized bending-beam electrochemical actuator Curr. Appl. Phys., 5 (2), 194-201, 2005
2005	PPy	device	Pyo	Kwak	M. Pyo and C. H. Kwak In situ scanning tunneling microscopy study on volume change of polypyrrole/poly(styrene sulfonate) Synth. Met., 150 (2), 133-137, 2005
2005	PPy	device	Ryu	Park	J. Ryu, J. Park, B. Kim, and J. O. Park Design and fabrication of a largely deformable sensorized polymer actuator Biosensors & Bioelectronics, 21 (5), 822-826, 2005
2005	PPy	performance	Pyo	Kwak	M. Pyo and C. H. Kwak In situ scanning tunneling microscopy study on volume change of polypyrrole/poly (styrene sulfonate) Synth. Met., 150 (2), 133-137, 2005
2005	PPy	performance	Spinks	Spinks	G. M. Spinks, T. E. Campbell, and G. G. Wallace Force generation from polypyrrole actuators Smart Mater. Struct., 14 (2), 406-412, 2005
2005	PPy	performance	Spinks	Spinks	G. M. Spinks, T. E. Campbell, and G. G. Wallace Force generation from polypyrrole actuators Smart Mater. Struct., 14 (2), 406-412, 2005
2005	PPy	model	Suarez	Otero	I. J. Suarez, T. F. Otero, and M. Marquez Diffusion coefficients in swelling polypyrrole: ESCR and Cottrell models J. Phys. Chem. B, 109 (5), 1723-1729, 2005
2005	PPy	device	Takashima	Kaneto	W. Takashima, K. Kanamori, S. S. Pandey, and K. Kaneto Patternable bi-ionic actuator: an example of new functionality of actuation, folding and unfolding of electrochemical spring Sens. Act. B, 110 (1), 120-124, 2005
2005	PPy	micro-act	Tsai	Madou	H.-K. A. Tsai, H. Xu, J. Zoval, and M. Madou Bi-layer polypyrrole artificial muscle valves for drug delivery systems SPIE, Smart Structures and Materials, Electroactive Polymers and Devices (EAPAD) San Diego, March 6-10, 2005.
2005	N/A	review	Baughman	Baughman	R. H. Baughman Playing nature's game with artificial muscles Science, 308 (Apr 1), 63-65, 2004
					top of page
2004	PPy	device	Andrews	Wallace	M. K. Andrews, M. L. Jansen, G. M. Spinks, D. Z. Zhou, and G. G. Wallace An integrated electrochemical sensor-actuator system Sens. Act. A, 114 (1), 65-72, 2004
2004	PPy	performance	Anquetil	Hunter	P. A. Anquetil, D. Rinderknecht, N. A. Vandesteeg, J. D. Madden, and I. W. Hunter Large strain actuation in polypyrrole actuators SPIE, Smart Structures and Materials, Electroactive Polymers and Devices (EAPAD), vol. 5385, p. 380-387, 2004
2004	PPy	mechanism	Careem	Skaarup	M. A. Careem, K. P. Vidanapathirana, S. Skaarup, and K. West Dependence of force produced by polypyrrole-based artificial muscles on ionic species involved Sol. State Ion., 175 (1-4), 725-728, 2004
2004	PPy	device	Hara	Kaneto	S. Hara, T. Zama, A. Ametani, W. Takashima, and K. Kaneto Enhancement in electrochemical strain of a polypyrrole-metal composite film actuator J. Mater. Chem., 14 (18), 2724-2725, 2004
2004	PPy	material	Hara	Kaneto	S. Hara, T. Zama, W. Takashima, and K. Kaneto Gel-like polypyrrole based artificial muscles with extremely large strain Polym. J., 36 (11), 933-936, 2004
2004	PPy	device	Hara	Kaneto	S. Hara, T. Zama, W. Takashima, and K. Kaneto Polypyrrole-metal coil composite actuators as artificial muscle fibres Synth. Met., 146 (1), 47-55, 2004
2004	PPy	material	Hara	Kaneto	S. Hara, T. Zama, W. Takashima, and K. Kaneto TFSI-doped polypyrrole actuator with 26% strain J. Mater. Chem., 14 (10), 1516-1517, 2004
2004	PPy	material	Hara	Kaneto	S. Hara, T. Zama, W. Takashima, and K. Kaneto Artificial muscles based on polypyrrole actuators with large strain and stress induced electrically Polym. J., 36 (2), 151-161, 2004
2004	PPy	device	Kanamori	Kaneto	K. Kanamori, W. Takashima, and K. Kaneto Simple metrology of actuation performance in bimorph actuator of conducting polymer ICSM, Int'l. Conf. Synthetic Metals, Wollongong, Australia, June 28 - July 2, 2004
2004	PPy	model	Madden	Madden	P. G. A. Madden, J. D. W. Madden, P. A. Anquetil, N. A. Vandesteeg, and I. W. Hunter The relation of conducting polymer actuator material properties to performance IEEE J. Ocean Eng., 29 (3), 696-705, 2004
2004	PPy	material	Onoda	Tada	M. Onoda and K. Tada Anisotropic bending machine using conducting polypyrrole IEICE Trans. Electron., E87C (2), 128-135, 2004
2004	PPy	model	Otero	Otero	T. F. Otero and J. Padilla Anodic shrinking and compaction of polypyrrole blend: electrochemical reduction under conformational relaxation kinetic control J. Electroanal. Chem., 561 (1), 167-171, 2004
2004	PPy	performance	Pandey	Kaneto	S. S. Pandey, W. Takashima, and K. Kaneto Conserved electrochemomechanical activities of polypyrrole film in complex buffer media Sens. Act. B, 102 (1), 142-147, 2004
2004	PPy	material	Pandey	Kaneto	S. S. Pandey, W. Takashima, and K. Kaneto Electrochemomechanical deformation in conducting copolymers containing pyrrole and anisidine moieties React. Funct. Polym., 58 (2), 103-110, 2004
2004	PPy	mechanism	Rajesh	Kaneto	Rajesh, S. S. Pandey, D. Kumar, W. Takashima, and K. Kaneto Electrochemomechanical deformation studies of [Fe(CN)6]3-ion doped conducting polypyrrole film Thin Solid Films, 467 (1-2), 227-230, 2004
2004	PPy	performance	Skaarup	Skaarup	S. Skaarup, L. Bay, and K. West Polypyrrole actuators working at 2 to 30 Hz ICSM, Int'l. Conf. Synthetic Metals, Wollongong, Australia June 28 - July 2, 2004
2004	PPy	performance	Spinks	Spinks	G. M. Spinks, B. B. Xi, D. Z. Zhou, V. T. Truong, and G. G. Wallace Enhanced control and stability of polypyrrole electromechanical actuators Synth. Met., 140 (2-3), 273-280, 2004
2004	PPy	material	Takashima	Kaneto	W. Takashima, S. S. Pandey, and K. Kaneto Improved cathodic expansions of electrochemomechanical behavior in polypyrrole films electrodeposited from aerosol OT emulsion Chem. Lett., 33 (8), 996-997, 2004
2004	PANi	performance	Lizarraga	Molina	L. Lizarraga, E. M. Andrade, and F. V. Molina Swelling and volume changes of polyaniline upon redox switching J. Electroanal. Chem., 561 (1), 127-135, 2004
2004	PANi	mechanism	Lu	Mattes	W. Lu and B. R. Mattes Factors influencing electrochemical actuation of polyaniline fibers in ionic liquids ICSM, Int'l. Conf. Synthetic Metals, Wollongong, Australia, June 28 - July 2, 2004
2004	PANi	device	Lu	Mattes	W. Lu, E. Smela, P. Adams, G. Zuccarello, and B. R. Mattes Development of solid-in-hollow electrochemical linear actuators using highly conductive polyaniline Chem. Mater., 16 (9), 1615-1621, 2004
2004	PANi	performance	Qi	Mattes	B. H. Qi, W. Lu, and B. R. Mattes Strain and energy efficiency of polyaniline fiber electrochemical actuators in aqueous electrolytes J. Phys. Chem. B, 108 (20), 6222-6227, 2004
2004	PANi	material	Takashima	Kaneto	W. Takashima, B. Dufour, S. S. Pandey, K. Kaneto, and A. Pron Electrochemically generated deformations of polyaniline film plasticized with di-2-butoxy-2-ethoxy-ethyl ester of sulfosuccinic acid Sens. Act. B, 99 (2-3), 601-607, 2004
2004	PANi	mechanism	Takashima	Kaneto	W. Takashima, M. Nakashima, S. S. Pandey, and K. Kaneto Enhanced electrochemomechanical activity of polyaniline films towards high pH region: contribution of Donnan effect Electrochim. Acta, 49 (24), 4239-4244, 2004
2004	PANi	micro-act	Zhou	Li	J. W. L. Zhou, H. Y. Chan, T. K. H. To, K. W. C. Lai, and W. J. Li Polymer MEMS actuators for underwater micromanipulation IEEE-ASME Trans. Mechatronics, 9 (2), 334-342, 2004
2004	PEDOT	mechanism	Vandesteeg	Hunter	N. Vandesteeg, P. A. Anquetil, and I. W. Hunter Poly(3,4-ethylenedioxythiophene) actuators, the role of cation and anion choice SPIE, Smart Structures and Materials, Electroactive Polymers and Devices (EAPAD), vol. 5385, p. 182-189, 2004
2004	PEDOT	material	Vidal	Chevrot	F. Vidal, C. Plesse, D. Teyssie, and C. Chevrot Long-life air working conducting semi-IPN/ionic liquid based actuator Synth. Met., 142, 287-291, 2004
2004	several	review	Madden	Madden	J. D. W. Madden, N. A. Vandesteeg, P. A. Anquetil, P. G. A. Madden, Arash Takshi, R. Z. Pytel, S. R. Lafontaine, P. A. Wieringa, and I. W. Hunter Artificial muscle technology: physical principles and naval prospects IEEE J. Ocean Eng., 29 (3), 706-728, 2004
					top of page
2003	PPy	micro-act	Berdichevsky	Lo	Y. Berdichevsky and Y.-H. Lo Polymer microvalve based on anisotropic expansion of polypyrrole Mat. Res. Soc. Symp. Fall 2003 Meeting Boston, (MRS), vol. 782, edited by D. A.LaVan, A. A. Ayon, M. J. Madou, M. E. McNie, and S. V. Prasad, p. A4.4.1 (Dec. 1-5).
2003	PPy	actuator	Joo	Pyo	J. Joo and M. Pyo Effects of cationic species on strain changes of polypyrrole doped with perchlorate ions Electrochem. Sol. State Lett., 6 (10), E27-E29
2003	PPy	actuator	Tada	Onoda	K. Tada, Y. Kato, and M. Onoda Preparation of sheet polypyrrole with vertical anisotropy: A self-organized bending-beam actuator Synth. Met., 135 (1-3), 101-102
2001	PPy	actuator	Onada	Tada	M. Onoda, T. Okamoto, and K. Tada Actuators based on steric effect from cation insertion and extraction Synth. Met., 119 (1-3), 279-280
2001	PPy	actuator	Okamoto	Onada	T. Okamoto, Y. Kato, K. Tada, and M. Onoda Actuator based on doping/undoping-induced volume change in anisotropic polypyrrole film Thin Solid Films, 393 (1-2), 383-387
2000	PPy	actuator	Okamoto	Onada	T. Okamoto, K. Tada, and M. Onoda Bending machine using anisotropic polypyrrole films Jpn. J. Appl. Phys. 2, 39 (5A), 2854-2858
2000	PPy	ion	Skaarup	Skaarup	S. Skaarup, K. West, L. M. W. K. Gunaratne, K. P. Vidanapathirana, and M. A. Careem Determination of ionic carriers in polypyrrole Sol. State Ion., 136, 577-582
1999	PPy	micro-act	Jager	Inganäs	E. W. H. Jager, E. Smela, and O. Inganäs On-chip microelectrodes for electrochemistry with moveable PPy bilayer actuators as working electrodes Sens. Act. B, 56, 73-78
1999	PPy	micro-act	Jager	Lundström	E. W. H. Jager, E. Smela, O. Inganäs, and I. Lundström Applications of polypyrrole microactuators Proc. SPIE's 6th Int. Symp. Smart Struc. Mater., Electroactive Polymer Actuators and Devices (EAPAD) Newport Beach, CA, (SPIE), vol. 3669, edited by Y. Bar-Cohen, p. 377-384 (1-2 March).
1998	PPy	actuator	Okuzaki	Kondo	H. Okuzaki, T. Kuwabara, and T. Kondo Role and effect of dopant ion on sorption-induced motion of polypyrrole films J. Polym. Sci. B, 36 (14), 2635-2642
1996	PPY	ion	Ehrenbeck	Juttner	C. Ehrenbeck and K. Juttner Ion conductivity and permselectivity measurements of polypyrrole membranes at variable states of oxidation Electrochim. Acta, 41 (11/12), 1815-1823
					top of page

Return to Congugated Polymer Actuators