Solvent-Induced Phase-Inversion and Electrical Actuation of Dielectric Copolymer Films

Yeonju Jang, Toshihiro Hirai

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DOI: 10.4236/msa.2011.23023                

Abstract

Block copolymers posses inherently the ability of form a variety of phase-separated microdomain structures. The lengths of block segments and the selectivity of the solvent are primary factors affecting the resultant morphology. This paper investigated the effect of casting solvents on the morphologies and electrical actuation of poly(methyl methacrylate)-poly(n-butyl acrylate)-poly(methyl methacrylate) (PMMA-PnBA-PMMA) triblock copolymer films comprising PMMA hard segment and PnBA soft segment. Transmission electron microscopy and confocal laser scanning microscopy observation revealed that PMMA and PnBA segments were assembled into various micro- and nano-sized phase structures where either of them formed continuous phase. This implies that continous phase could be inversed by used casting solvents. Solvent-dependent phase morphologies had a significant effect on the electrical actuation results. Increase of the PnBA contents and the continuous phases of PnBA soft segments improved both of electrical actuation and dielectric constant, indicating that solvent-induced phase separation modulates the electrical actuation of dielectric films. The significance of the role of solvent selectivity and the major continuous phase of the polymer in defining the morphology and electrical actuation of the self-assembled block copolymer structure are discussed.

Keywords

Actuator, Acrylic Triblock Copolymers, Electrical Actuation, Dielectric Properties

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	R. Kornbluh, R. Pelrine, Q. Pei, S. Oh and J. Joseph, “Ultrahigh Strain Response of Field-Actuated Elastomeric Polymers,” Proceedings of SPIE, 2002, pp. 51-64.
[2]	R. Pelrine, R. Kornbluh, Q. Pei and J. Joseph, “Highspeed Electrically Actuated Elastomers with over 100% Strain,” Science, Vol. 287, No. 5454, 2000, pp. 836-839. doi:10.1126/science.287.5454.836
[3]	P. Carpi, D. de Rossi, R. Kornbluh, R. Pelrine and P. Sommer-Larsen, “Dielectric Elastomers as Electromechanical Transducers: Fundamentals, Materials, Devices, Models and Applications of an Emerging Electroactive Polymer Technology,” Elsevier, Amsterdam, 2008.
[4]	L. E. Cross, “Ferroelectric Ceramics: Materials and Application Issues,” Ceramic Transactions, Vol. 68, 1996, pp. 15-55.
[5]	K. B. Hathaway and A. E. Clark, “Magnetostrictive Materials,” MRS Bulletin, Vol. 18, No. 4, 1993, pp. 34-41.
[6]	S. M. Wayman, “Shape Memory Alloys,” MRS Bulletin, Vol. 18, No. 4, 1993, pp. 49-56.
[7]	A. J. Lovinger, “Ferroelectric Polymers,” Science, Vol. 220, No. 4602, 1983, pp. 1115-1121. doi:10.1126/science.220.4602.1115
[8]	J. Kim, Y. Kang and S. Yun, “Force Measurement of Electro-Active Paper Actuators by Microbalance,” Sensors and Actuators A: Physical, Vol. 133, No. 2, 2007, pp. 401-406. doi:10.1016/j.sna.2006.04.019
[9]	H. H. Winter, D. B. Scott, W. Gronski, S. Okamoto and T. Hashimoto, “Ordering by Flow near the Disorder-Order Transition of Triblock Copolymer Styrene-Isoprene-Styrene,” Macromolecules, Vol. 26, No. 26, 1993, pp. 7236-7244. doi:10.1021/ma00078a019
[10]	Y. Miura, T. Kaneko, K. Satoh, K. Kamigaito, H. Jinnai and Y. Okamoto, “AxBAx-Type Block-Graft Polymers with Soft Methacrylate Middle Segments and Hard Styrene Outer Grafts: Synthesis, Morphology, and Mechanical Properties,” Asian Journal of Chemistry, Vol. 2, No. 5, 2007, pp. 662-672. doi:10.1002/asia.200600403
[11]	W.-K. Lee, H.-D. Kim and E.-Y. Kim, “Morphological Reorientation by Extensional Flow Deformation of a Triblock Copolymer Styrene-Isoprene-Styrene,” Current Applied Physics, Vol. 6, No. 4, 2006, pp. 718-722. doi:10.1016/j.cap.2005.04.026
[12]	R. Shankar, T. K. Ghosh and R. J. Spontak, “Mechanical and Actuation behavior of Electroactive Nanostructured Polymers,” Sensors and Actuators A: Physical, Vol. 151, No. 1, 2009, pp. 46-52. doi:10.1016/j.sna.2009.01.002
[13]	R. Shankar, T. K. Ghosh and R. J. Spontak, “Electroactive Nanostructured Polymers as Tunable Actuators,” Advanced Materials, Vol. 19, No. 17, 2007, pp. 2218-2223. doi:10.1002/adma.200602644
[14]	R. Pelrine, R. Kornbluh and G. Kofod, “High-Strain Actuator Materials Based on Dielectric Elastomers,” Advanced Materials, Vol. 12, No. 16, 2000, pp. 1223-1225. doi:10.1002/1521-4095(200008)12:16<1223::AID-ADMA1223>3.0.CO;2-2
[15]	R. Kornbluh, R. Pelrine, J. Joseph, R. Heydt, Q. Pei and S. Chiba, “High-Field Electrostriction of Elastomeric Polymer Dielectrics for Actuation,” Proceeding of SPIE, Vol. 3669, 1999, pp. 149-161. doi:10.1117/12.349672
[16]	G. Kofod, R. Kornbluh, R. Pelrine and P. Sommer-Larsen, “Actuation Response of Polyacrylate Dielectric Elastomers,” Proceeding of SPIE, Vol. 4329, 2001, pp. 141-147. doi:10.1117/12.432638
[17]	G. Kofod, P. Sommer-Larsen, R. Kornbluh and R. Pelrine, “Actuation Response of Polyacrylate Dielectric Elastomers,” Journal of Intelligent Material Systems and Structures, Vol. 14, No. 12, 2003, pp. 787-793. doi:10.1177/104538903039260
[18]	G. Gallone, F. Carpi, D. de Rossi, G. Levita and A. Marchetti, “Dielectric Constant Enhancement in a Silicone Elastomer Filled with Lead Magnesium Niobate-Lead Titanate,” Materials Science and Engineering: C, Vol. 27, No. 1, 2007, pp. 110-116. doi:10.1016/j.msec.2006.03.003
[19]	F. Carpi and D. de Rossi, “Improvement of Electromechanical Actuating Performances of a Silicone Dielectric Elastomer Dispersion of Titanium Dioxde Powder,” IEEE Transactions on Dielectrics and Electrical Insulation, Vol. 12, No. 4, 2005, pp. 835-843. doi:10.1109/TDEI.2005.1511110
[20]	A. J. Moulson and J. M. Herbert, “Electroceramics,” Chapman & Hall, London, 1990.
[21]	G. Gallone, F. Galantini and F. Carpi, “Perspectives for New Dielectric Elastomers with Improved Electromechanical Actuation Performance: Composites versus Blends,” Polymer International, Vol. 59, No. 3, 2010, pp. 400-406. doi:10.1002/pi.2765
[22]	K. Ishiura, “接着の技術 (Settyaku No Gijutsu),” Vol. 25, 2005, pp. 38-43.
[23]	Y. Morishita, T. Kurihara, K. Hamada and K. Ishiura, “A Novel (Meth)Acrylic Block Co-Polymers Synthesis, Characteristics, and Applications,” The 8th SPSJ International Polymer Conference, 28P2G5-102b, 2005, p. 573.
[24]	R. Palakodeti and M. R. Kessler, “Influence of Frequency and Prestrain on the Mechanical Efficiency of Dielectric Electroactive Polymer Actuators,” Materials Letters, Vol. 60, No. 29-30, 2006, pp. 3437-3440. doi:10.1016/j.matlet.2006.03.053
[25]	H. R. Choi, K. Jung, N. H. Chuc, M. Jung, I. Koo, J. Lee, J. Nam and M. Cho, “Effects of Prestrain on Behavior of Dielectric Elastomer Actuator,” Proceeding of SPIE, Vol. 5759, 2005, pp. 283-291. doi:10.1117/12.599363
[26]	X. Zhang, M. Wissler, B. Jaehne, R. Breonnimann and G. Kovacs, “Eletroactive Polymer Actuators and Devices (EAPAD),” Smart Structures and Materials: SPIE, Vol. 5385, 2004, pp. 78-86.
[27]	A. O’Halloran and F. O’Malley, “Materials and Technologies for Artificial Muscle: A Review for the Mechatronic Muscle Project,” In: P. J. Prendergast and P. E. McHugh, Eds., Topics in Bio-Mechanical Engineering, Trinity Centre for Bioengineering & National Centre for Biomedical Engineering Science, 2004, pp. 184-215.
[28]	D. W. van Krevelen and K. te Nijenhuis, “Properties of Prolymers,” 4th Edition, Elsevier, Oxford, Chap. 7, 2008.
[29]	D. W. van Krevelen and K. te Nijenhuis, “Properties of Prolymers,” 4th Edition, Elsevier, Oxford, Chap. 11, 2008.
[30]	J. Liu, T. Liu and S. Kumar, “Effect of Solvent Solubility Parameter on SWNT Dispersion in PMMA,” Polymer, Vol. 46, No. 10, 2005, pp. 3419-3424. doi:10.1016/j.polymer.2005.02.086
[31]	Q. M. Zhang, H. Li, M. Poh, F. Xia, Z. Y. Cheng, H. Xu and C. Huang, “An All-Organic Composite Actuator Material with a High Dielectric Constant,” Nature, Vol. 19, No. 419, 2002, pp. 284-287. doi:10.1038/nature01021
[32]	S. Ashley, “Artificial Muscles,” Scientific American, Vol. 289, No. 4, October 2003, pp. 52-59. doi:10.1038/scientificamerican1003-52
[33]	M. E. Seitz, W. R. Burghardt, K. T. Faber and K. R. Shull, “Self-Assembly and Stress Relaxation in Acrylic Triblock Copolymer Gels,” Macromolecules, Vol. 40, No. 4, 2007, pp. 1218-1226. doi:10.1021/ma061993+
[34]	R. D. Deanin, “Encyclopedia of Polymer Science and Technology, Wiley, New York, Chap. 7, 1977.
[35]	H. Burrel, “Polymer Handbook,” Interscience, New York, 1975.
[36]	K. Thongsak, R. Kunanuruksapong, A. Sirivat and W. Lerdwijitjarud, “Electroactive Styrene-Isoprene-Stryene Triblock Copolymer: Effects of Morphology and Electric Field,” Materials Science and Engineering: A, Vol. 527, No. 10-11, 2010, pp. 2504-2509. doi:10.1016/j.msea.2010.01.036