A review of piezoelectric polymers as functional materials for electromechanical transducers

Smart Materials and Structures

Volumn 23, Issue 3, 2014, Pages

  Ramadan, Khaled S ^a   Sameoto, D ^a   Evoy, S ^a  

^a UNIVERSITY OF ALBERTA   (Canada)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 84894283149     PISSN: 09641726     EISSN: 1361665X     Source Type: Journal    
DOI: 10.1088/0964-1726/23/3/033001     Document Type: Review

References (125)

1. Curie J and Curie P 1880 Development by pressure of polar electricity in hemihedral crystals with inclined faces Bull. Soc. Min. France 3 90
2. Heywang W, Lubitz K and Wersing W 2008 Piezoelectricity: Evolution and Future of a Technology (Berlin: Springer)
3. Setter N, Damjanovic D, Eng L, Fox G, Gevorgian S, Hong S, Kingon A, Kohlstedt H, Park N and Stephenson G 2006 Ferroelectric thin films: review of materials, properties, and applications J. Appl. Phys. 100 051606
4. Tadigadapa S and Materi K 2009 Piezoelectric MEMS sensors: state-of-the-art and perspectives Meas. Sci. Technol. 20 092001
5. Liu C 2007 Recent developments in polymer MEMS Adv. Mater. 19 3783-90
6. Becker H and Gärtner C 2008 Polymer microfabrication technologies for microfluidic systems Anal. Bioanal. Chem. 390 89-111
7. Kumar D and Sharma R C 1998 Advances in conductive polymers Eur. Polym. J. 34 1053-60
8. Bar-Cohen Y, Kim K J, Choi H R and Madden J D 2007 Electroactive polymer materials Smart Mater. Struct. 16 S195-6
9. McGehee M and Heeger A 2000 Semiconducting (conjugated) polymers as materials for solid-state lasers Adv. Mater. 12 1655-68
10. Pan T and Wang W 2011 From cleanroom to desktop: emerging micro-nanofabrication technology for biomedical applications Ann. Biomed. Eng. 39 600-20
11. Tiwari R and Garcia E 2011 The state of understanding of ionic polymer metal composite architecture: a review Smart Mater. Struct. 20 083001
12. Jean-Mistral C, Basrour S and Chaillout J 2010 Comparison of electroactive polymers for energy scavenging applications Smart Mater. Struct. 19 085012
13. Marauska S, Hrkac V, Dankwort T, Jahns R, Quenzer H J, Knöchel R, Kienle L and Wagner B 2012 Sputtered thin film piezoelectric aluminum nitride as a functional MEMS material Microsystem Technologies 18 787-95
14. Senturia S D 2001 Microsystem Design (Boston, MA: Kluwer Academic Publishers)
15. Harrison J S and Ounaies Z 2002 Piezoelectric polymers Encyclopedia of Polymer Science and Technology (New York: Wiley) 474-98
16. Dargaville T R, Celina M C, Elliott J M, Chaplya P M, Jones G D, Mowery D M, Assink R A, Clough R L and Martin J W 2005 Characterization, Performance and Optimization of PVDF as a Piezoelectric Film for Advanced Space Mirror Concepts (Livermore, CA: Sandia National Laboratories) no. SAND 2005-6846
17. Kim J Y, Cheng A and Yu-chong Tai 473 Parylene-C as a piezoelectric material
18. Park C, Ounaies Z, Wise K E and Harrison J S 2004 In situ poling and imidization of amorphous piezoelectric polyimides Polymer 45 5417-25
19. Li C, Wu P M, Lee S, Gorton A, Schulz M J and Ahn C H 2008 Flexible dome and bump shape piezoelectric tactile sensors using PVDF-TrFE copolymer J. Microelectromech. Syst. 17 334-41
20. Gross B, Gerhard-Multhaupt R, Berraissoul A and Sessler G M 1987 Electron-beam poling of piezoelectric polymer electrets J. Appl. Phys. 62 1429-32
21. Qiu X 2010 Patterned piezo-, pyro-, and ferroelectricity of poled polymer electrets J. Appl. Phys. 108 011101
22. Honzumi M, Ueno A, Hagiwara K, Suzuki Y, Tajima T and Kasagi N 2010 Soft-x-ray-charged vertical electrets and its application to electrostatic transducers 635
23. Atkinson G M, Pearson R E, Ounaies Z, Park C, Harrison J S, Dogan S and Midkiff J A 2003 Novel piezoelectric polyimide MEMS 782
24. Safari A, Janas V F and Bandyopadhyay A 1997 Development of fine-scale piezoelectric composites for transducers AICHE J. 43 2849-56
25. Levassort F, Lethiecq M and Desmare R 1999 Effective electroelastic moduli of 3-3(0-3) piezocomposites IEEE Trans. Ultrason. Ferroelectr. Freq. Control 46 1028-34
26. Guinovart-Diaz R, Bravo-Castillero J, Rodriguez-Ramos R, Sabina F and Martinez-Rosado R 2001 Overall properties of piezocomposite materials 1-3 Mater. Lett. 48 93-8
27. Kar-Gupta R and Venkatesh T 2007 Electromechanical response of 1-3 piezoelectric composites: an analytical model Acta Mater. 55 1093-108
28. Park K et al 2012 Flexible nanocomposite generator made of BaTiO3 nanoparticles and graphitic carbons Adv. Mater. 24 2999-3004
29. Hillenbrand J and Sessler G M 2004 Quasistatic and dynamic piezoelectric coefficients of polymer foams and polymer film systems IEEE Trans. Dielectr. Electr. Insul. 11 72-9
30. Sessler G and West J 1962 Self-biased condenser microphone with high capacitance J. Acoust. Soc. Am. 34 1787-8
31. Gerhard-Multhaupt R 2002 Less can be more. Holes in polymers lead to a new paradigm of piezoelectric materials for electret transducers IEEE Trans. Dielectrics and Electrical Insulation 9 850-9
32. Bauer S, Gerhard-Multhaupt R and Sessler G M 2004 Ferroelectrets: soft electroactive foams for transducers Phys. Today 57 37
33. Roh Y, Varadan V V and Varadan V K 2002 Characterization of all the elastic, dielectric, and piezoelectric constants of uniaxially oriented poled PVDF films IEEE Trans. Ultrasonics, Ferroelectrics Frequency Control 49 836-47
34. Piezoelectric Films Technical Information. Available: www.piezotech.fr/image/documents/22-31-32-33-piezotech-piezoelectric-films- leaflet.pdf [2013, 02/26]
35. Sharma T, Je S, Gill B and Zhang J X J 2012 Patterning piezoelectric thin film PVDF-TrFE based pressure sensor for catheter application Sensors Actuators A 177 87-92
36. Parylene Properties and Characteristics. Available: www.vp-scientific. com/parylene-properties.htm [2013, 3/12/2013]
37. Kim J Y, Nandra M and Yu-chong T 2012 Cantilever actuated by piezoelectric Parylene-C 1141
38. Lallart M, Cottinet P, Lebrun L, Guiffard B and Guyomar D 2010 Evaluation of energy harvesting performance of electrostrictive polymer and carbon-filled terpolymer composites J. Appl. Phys. 108 034901
39. Ramaratnam A and Jalili N 2006 Reinforcement of piezoelectric polymers with carbon nanotubes: pathway to next-generation sensors J. Intell. Mater. Syst. Struct. 17 199-208
40. Graz I, Krause M, Bauer-Gogonea S, Bauer S, Lacour S P, Ploss B, Zirkl M, Stadlober B and Wagner S 2009 Flexible active-matrix cells with selectively poled bifunctional polymer-ceramic nanocomposite for pressure and temperature sensing skin J. Appl. Phys. 106 034503
41. Ye H, Shao W and Zhen L 2013 Crystallization kinetics and phase transformation of poly (vinylidene fluoride) films incorporated with functionalized BaTiO3 nanoparticles J. Appl. Polym. Sci. 129 2940-9
42. Dodds J S, Meyers F N and Loh K J 2012 Piezoelectric characterization of PVDF-TrFE thin films enhanced with ZnO nanoparticles IEEE Sensors J. 12 1889-90
43. Shirinov A and Schomburg W 2008 Pressure sensor from a PVDF film Sensors Actuators A 142 48-55
44. Jo S-E, Kim M-S and Kim Y-J 2012 A resonant frequency switching scheme of a cantilever based on polyvinylidene fluoride for vibration energy harvesting Smart Mater. Struct. 21 015007
45. Lee S, Bordatchev E V and Zeman M J 2008 Femtosecond laser micromachining of polyvinylidene fluoride (PVDF) based piezo films J. Micromech. Microeng. 18 045011
46. Hong C, Huang S, Shieh J and Chen S 2012 Enhanced piezoelectricity of nanoimprinted sub-20 nm poly (vinylidene fluoride-trifluoroethylene) copolymer nanograss Macromolecules 45 1580-6
47. Hong C, Huang S, Shieh J, Chen S and Chen A 2012 Piezoelectricity of sub-20-nm nanoimprinted PVDF-TrFE nanograss (Piscataway, NJ: IEEE) 1336
48. Chen A, Lin K, Hong C, Liou T, Shieh J and Chen S 2012 Flexible tactile sensors based on nanoimprinted sub-20 NM piezoelectric copolymer nanograss films Sensors 1-4
49. Parylene deposition process. Available: http://scscoatings.com/what-is- parylene/parylene-deposition.aspx last accessed 31 May 2013
50. Kim J Y 2013 Parylene-C as a new piezoelectric material PhD Thesis California Institute of Technology
51. Wang Y R, Zheng J M, Ren G Y, Zhang P H and Xu C 2011 A flexible piezoelectric force sensor based on PVDF fabrics Smart Mater. Struct. 20 045009
52. Dahiya R S, Valle M, Metta G, Lorenzelli L and Adami A 2009 Design and fabrication of posfet devices for tactile sensing 1881
53. Dahiya R S, Cattin D, Adami A, Collini C, Barboni L, Valle M, Lorenzelli L, Oboe R, Metta G and Brunetti F 2011 Towards tactile sensing system on chip for robotic applications IEEE Sensors J. 11 3216-26
54. Schulze R, Gessner T, Schueller M, Forke R, Billep D, Heinrich M, Sborikas M and Wegener M 2012 Integration of piezoelectric polymer transducers into microsystems for sensing applications 1
55. Zirkl M, Sawatdee A, Helbig U, Krause M, Scheipl G, Kraker E, Ersman P A, Nilsson D, Platt D and Bodö P 2011 An all-printed ferroelectric active matrix sensor network based on only five functional materials forming a touchless control interface Adv. Mater. 23 2069-74
56. Prashanthi K, Miriyala N, Gaikwad R D, Moussa W, Rao V R and Thundat T 2013 Vibtrational energy harvesting using photo-patternable piezoelectric nanocomposite cantilevers Nano Energy 2 923-32
57. Xu S, Yeh Y, Poirier G, McAlpine M C, Register R A and Yao N 2013 Flexible piezoelectric PMN-PT nanowire-based nanocomposite and device Nano Lett. 13 2393-8
58. Levassort F, Hladky-Hennion A, Le Khanh H, Tran-Huu-Hue P, Lethiecq M and Pham Thi M 2010 0-3 and 1-3 piezocomposites based on single crystal PMN-PT for transducer applications Adv. Appl. Ceram. 109 162-8
59. Zhou D, Cheung K F, Chen Y, Lau S T, Zhou Q, Shung K, Luo H S, Dai J and Chan H L W 2011 Fabrication and performance of endoscopic ultrasound radial arrays based on PMN-PT single crystal/epoxy 1-3 composite IEEE Trans. on Ultrasonics, Ferroelectrics and Frequency Control 58 477-84
60. Liu C, Djuth F, Li X, Chen R, Zhou Q and Shung K K 2012 Micromachined high frequency PMN-PT/epoxy 1-3 composite ultrasonic annular array Ultrasonics 52 497
61. Tsang S-H, Ma A H, Karim K S, Parameswaran A and Leung A M 2008 Monolithically fabricated polymermems 3-axis thermal accelerometers designed for automated wirebonder assembly 880
62. Marnat L, Arevalo Carreno A, Conchouso D, Galicia Martinez M, Foulds I and Shamim A 2013 New movable plate for efficient millimeter wave vertical on-chip antenna IEEE Trans. Antennas and Propagation 61 1608-15
63. Tsang S, Simard K, Foulds I, Izadi H, Karim K and Parameswaran M 2009 Thin film transistor (TFT) sensing elements fabricated in surface micromachined polymermems for a differential calorimetric flow sensor (Piscataway, NJ: IEEE) 583
64. Atkinson G M, Pearson R E, Ounaies Z, Park C, Harrison J S and Midkiff J A 2003 Piezoelectric polyimide tactile sensors 308
65. Deshmukh S and Ounaies Z 2010 Active single walled carbon nanotube-polymer composites (Berlin: Springer) 103-10
66. Zhang Y, Wang S, Liu D, Zhang Q, Wang W, Ren B, Zhao X and Luo H 2011 Fabrication of angle beam two-element ultrasonic transducers with PMN-PT single crystal and PMN-PT/epoxy 1-3 composite for NDE applications Sensors Actuators A 168 223
67. Matt H and di Scalea F L 2007 Macro-fiber composite piezoelectric rosettes for acoustic source location in complex structures Smart Mater. Struct. 16 1489
68. Yang Y, Tang L and Li H 2009 Vibration energy harvesting using macro-fiber composites Smart Mater. Struct. 18 115025
69. Epo-Tek 301 Datasheet 2012, last update September 2012 Available: www.epotek.com/sscdocs/datasheets/301.PDF last accessed 4 June 2013 - ref-separator -
70. Smith W A 1989 The role of piezocomposites in ultrasonic transducers 755
71. Lewis R, Allsopp D, Shields P, Satka A, Yu S, Topolov V Y and Bowen C 2012 Nano-imprinting of highly ordered nano-pillars of lithium niobate (LiNbO3) Ferroelectrics 429 62-8
72. Sun P, Wang G, Wu D, Zhu B, Hu C, Liu C, Djuth F T, Zhou Q and Shung K K 2010 High frequency PMN-PT 1-3 composite transducer for ultrasonic imaging application Ferroelectrics 408 120-8
73. Baek S, Rzchowski M S and Aksyuk V A 2012 Giant piezoelectricity in PMN-PT thin films: beyond PZT MRS Bull. 37 1022-9
74. Kim K, Hsu D K, Ahn B, Kim Y and Barnard D J 2010 Fabrication and comparison of PMN-PT single crystal, PZT and PZT-based 1-3 composite ultrasonic transducers for NDE applications Ultrasonics 50 790
75. Prashanthi K, Naresh M, Seena V, Thundat T and Ramgopal Rao V 2012 A novel photoplastic piezoelectric nanocomposite for MEMS applications J. Microelectromech. Syst. 21 259-61
76. Ramadan K S, Nasr T and Foulds I G 2013 Development of an SU-8 MEMS process with two metal electrodes using amorphous silicon as a sacrificial material J. Micromech. Microeng. 23 35037-49
77. Sameoto D, Tsang S and Parameswaran M 2007 Polymer MEMS processing for multi-user applications Sensors Actuators A 134 457-64
78. Kandpal M, Sharan C, Poddar P, Prashanthi K, Apte P R and Ramgopal Rao V 2012 Photopatternable nano-composite (SU-8/ZnO) thin films for piezo-electric applications Appl. Phys. Lett. 101 104102
79. Doring J, Bovtun V, Gaal M, Bartusch J, Erhard A, Kreutzbruck M and Yakymenko Y 2012 Piezoelectric and electrostrictive effects in ferroelectret ultrasonic transducers J. Appl. Phys. 112 084505
80. Doring J, Bovtun V, Bartusch J, Erhard A, Kreutzbruck M and Yakymenko Y 2010 Nonlinear electromechanical response of the ferroelectret ultrasonic transducers Appl. Phys. A 100 479-85
81. An Z, Mao M, Cang J, Zhang Y and Zheng F 2012 Significantly improved piezoelectric thermal stability of cellular polypropylene films by high pressure fluorination and post-treatments J. Appl. Phys. 111 024111
82. Saarimaki E, Paajanen M, Savijarvi A, Minkkinen H, Wegener M, Voronina O, Schulze R, Wirges W and Gerhard-Multhaupt R 2006 Novel heat durable electromechanical film: processing for electromechanical and electret applications IEEE Trans. Dielectrics and Electrical Insulation 13 963-72
83. Fang P, Qiu X, Wirges W, Gerhard R and Zirkel L 2010 Polyethylene- naphthalate (PEN) ferroelectrets: cellular structure, piezoelectricity and thermal stability IEEE Trans. Dielectrics and Electrical Insulation 17 1079-87
84. Zhang X, Huang J, Wang X and Xia Z 2010 Piezoelectricity and dynamic characteristics of laminated fluorocarbon films IEEE Trans. Dielectrics and Electrical Insulation 17 1001-7
85. Zhang X, Hillenbrand J, Sessler G, Haberzettl S and Lou K 2012 Fluoroethylenepropylene ferroelectrets with patterned microstructure and high, thermally stable piezoelectricity Appl. Phys. A 107 621-9
86. Tsai J, Wang J and Su Y 2013 Piezoelectric rubber films for human physiological monitoring and energy harvesting 841
87. Feng Y, Hagiwara K, Iguchi Y and Suzuki Y 2012 Trench-filled cellular parylene electret for piezoelectric transducer Appl. Phys. Lett. 100 262901
88. Feng Y and Suzuki Y 2013 All-polymer soft-x-ray-charged piezoelectret with embedded PEDOT electrode 865
89. Kirjavainen K 1987 Electromechanical film and procedure for manufacturing same US Patent 4,654,546
90. Wegener M, Tuncer E, Wirges W, Gerhard-Multhaupt R, Dansachmuller M, Bauer-Gogonea S, Schwodiauer R and Bauer S 2004 Ferroelectrets: highly anisotropic electrically charged polymer foams for electromechanical transducer applications (Piscataway, NJ: IEEE) 1138
91. Zhang X, Hillenbrand J and Sessler G M 2004 Piezoelectric d33 coefficient of cellular polypropylene subjected to expansion by pressure treatment Appl. Phys. Lett. 85 1226-8
92. Wan Y, Fan L and Zhong Z 2012 Finite element modeling of temporal evolution of the quasi-piezoelectric d33 coefficient of cellular piezoelectret Polypropylene film Comput. Mater. Sci. 55 54-9
93. Hu Z and Von Seggern H 2006 Breakdown-induced polarization buildup in porous fluoropolymer sandwiches: a thermally stable piezoelectret J. Appl. Phys. 99 024102
94. Wang J, Hsu T, Yeh C, Tsai J and Su Y 2012 Piezoelectric polydimethylsiloxane films for MEMS transducers J. Micromech. Microeng. 22 015013
95. Hillenbrand J and Sessler G M 2000 Piezoelectricity in cellular electret films IEEE Trans. Dielectrics and Electrical Insulation 7 537-42
96. Karttunen M, Paajanen M, Härkki O, Kortet S and Orko I 2013 Thermally more durable electromechanical films by POSS nanomodification Key Eng. Mater. 538 65-8
97. PI Ceramic - Advanced Piezoelectric Materials: Typical Parameters of Piezoelectric Ceramics, PZT Material - Piezoceramic Materials. Available: www.piceramic.com/piezo-materials-2.php [2013, 3/20/2013]
98. Crisler D F, Cupal J J and Moore A R 1968 Dielectric, piezoelectric, and electromechanical coupling constants of zinc oxide crystals Proc. IEEE 56 225-6
99. Poterala S F, Trolier-McKinstry S, Meyer R J and Messing G L 2011 Processing, texture quality, and piezoelectric properties of C textured (1-x) Pb (Mg1/3Nb2/3) TiO3-xPbTiO3 ceramics J. Appl. Phys. 110 014105
100. Tiwana M I, Redmond S J and Lovell N H 2012 A review of tactile sensing technologies with applications in biomedical engineering Sensors Actuators A 179 17-31
101. Lindahl O A, Constantinou C E, Eklund A, Murayama Y, Hallberg P and Omata S 2009 Tactile resonance sensors in medicine J. Med. Eng. Technol. 33 263-73
102. Buchberger G, Schwodiauer R and Bauer S 2008 Flexible large area ferroelectret sensors for location sensitive touchpads Appl. Phys. Lett. 92 123511
103. Petroni S, Guido F, Torre B, Falqui A, Todaro M T, Cingolani R and De Vittorio M 2012 Tactile multisensing on flexible aluminum nitride Analyst 137 5260-4
104. Akiyama M, Morofuji Y, Kamohara T, Nishikubo K, Ooishi Y, Tsubai M, Fukuda O and Ueno N 2007 Preparation of oriented aluminum nitride thin films on polyimide films and piezoelectric response with high thermal stability and flexibility Adv. Funct. Mater. 17 458-62
105. Rojas J P, Sevilla G T and Hussain M M 2013 Structural and electrical characteristics of high-k/metal gate metal oxide semiconductor capacitors fabricated on flexible, semi-transparent silicon (100) fabric Appl. Phys. Lett. 102 064102
106. Kim H, Kim J and Kim J 2011 A review of piezoelectric energy harvesting based on vibration Int. J. Precision Eng. Manufacturing 12 1129-41
107. Saadon S and Sidek O 2011 A review of vibration-based/MEMS/piezoelectric energy harvesters Energy Convers. Manag. 52 500
108. Anton S R and Sodano H A 2007 A review of power harvesting using piezoelectric materials (2003-2006) Smart Mater. Struct. 16 R1
109. Cook-Chennault K, Thambi N and Sastry A 2008 Powering MEMS portable devices - a review of non-regenerative and regenerative power supply systems with special emphasis on piezoelectric energy harvesting systems Smart Mater. Struct. 17 043001
110. Lee C, Joo J, Han S, Lee J and Koh S 2005 Poly (vinylidene fluoride) transducers with highly conducting poly (3, 4-ethylenedioxythiophene) electrodes Synth. Metals 152 49-52
111. Patel I, Siores E and Shah T 2010 Utilisation of smart polymers and ceramic based piezoelectric materials for scavenging wasted energy Sensors Actuators A 159 213-8
112. Tang L and Yang Y 2012 A nonlinear piezoelectric energy harvester with magnetic oscillator Appl. Phys. Lett. 101 094102
113. Leonov V 2011 Energy harvesting for self-powered wearable devices Wearable Monitoring Systems (Berlin: Springer) 27-49
114. Chao P 2011 Energy harvesting electronics for vibratory devices in self-powered sensors IEEE Sensors J. 11 3106-21
115. Zhang L, Oh S R, Wong T C, Tan C Y and Yao K 2013 Piezoelectric polymer multilayer on flexible substrate for energy harvesting IEEE Trans. Ultrasonics, Ferroelectrics and Frequency Control 60 2013-20
116. Xu T, Siochi E J, Kang J H, Zuo L, Zhou W, Tang X and Jiang X 2013 Energy harvesting using a PZT ceramic multilayer stack Smart Mater. Struct. 22 065015
117. Rossing T D 2007 Springer Handbook of Acoustics (Berlin: Springer)
118. Jadidian B, Hagh N M, Winder A A and Safari A 2009 25 MHz ultrasonic transducers with lead- free piezoceramic, 1-3 PZT fiber-epoxy composite, and PVDF polymer active elements IEEE Trans. Ultrasonics, Ferroelectrics and Frequency Control 56 368-78
119. Zhou Q, Lau S, Wu D and Kirk Shung K 2011 Piezoelectric films for high frequency ultrasonic transducers in biomedical applications Prog. Mater. Sci. 56 139-74
120. Lee S T F, Lam K H, Zhang X M and Chan H L 2011 Lead-free BSZT/Epoxy 1-3 composites for ultrasonic transducer applications Adv. Mater. Res. 254 90-3
121. Ko W-C, Tseng C-K, Leu Y, Wu W-J, Lee A S-Y and Lee C-K 2010 Use of 2-(6-mercaptohexyl) malonic acid to adjust the morphology and electret properties of cyclic olefin copolymer and its application to flexible loudspeakers Smart Mater. Struct. 19 055007
122. Feng G and Tsai M 2010 Acoustic emission sensor with structure-enhanced sensing mechanism based on micro-embossed piezoelectric polymer Sensors Actuators A 162 100-6
123. MEMS Accelerometers - MEMS and Sensors - Analog Devices. Available: www.analog.com/en/mems-sensors/mems-accelerometers/products/index. html#iSensor-MEMS-Accelerometer-Subsytems [2013, 3/28/2013]
124. Hillenbrand J, Kodejska M, Garcin Y, Seggern H V and Sessler G M 2010 High-sensitivity piezoelectret-film accelerometers IEEE Trans. Dielectrics Electrical Insulation 17 1021-7
125. Hillenbrand J, Haberzettl S, Motz T and Sessler G 2011 Electret accelerometers: physics and dynamic characterization J. Acoust. Soc. Am. 129 3682