The ability of certain materials to convert electrical stimuli into mechanical deformation, and vice versa, is a prized property. Not surprisingly, applications of such so-called piezoelectric materials are broad—ranging from energy harvesting to self-powered sensors. In this perspective, written in the form of question-answers, we highlight a relatively understudied electromechanical coupling called flexoelectricity that appears to have tantalizing implications in topics ranging from biophysics to the design of next-generation multifunctional nanomaterials.
Issue Section:
Review Article
Topics:
Deformation,
Design,
Energy harvesting,
Multifunctional materials,
Piezoelectric materials,
Piezoelectricity,
Polarization (Electricity),
Polarization (Light),
Polarization (Waves),
Strain gradient,
Sensors,
Biology,
Elasticity,
Nanomaterials,
Graphene,
Biophysics,
Micromechanics (Engineering),
Modeling,
Nanotechnology
References
1.
Nowick
, A. S.
, 2005
, Crystal Properties Via Group Theory
, Cambridge University Press
, New York
.2.
Tagantsev
, A. K.
, 1986
, “Piezoelectricity and Flexoelectricity in Crystalline Dielectrics
,” Phys. Rev. B
, 34
(8
), p. 5883
.3.
Maranganti
, R.
, Sharma
, N. D.
, and Sharma
, P.
, 2006
, “Electromechanical Coupling in Nonpiezoelectric Materials Due to Nanoscale Nonlocal Size Effects: Green's Function Solutions and Embedded Inclusions
,” Phys. Rev. B
, 74
(1
), p. 014110
.4.
Cross
, L. E.
, 2006
, “Flexoelectric Effects: Charge Separation in Insulating Solids Subjected to Elastic Strain Gradients
,” J. Mater. Sci.
, 41
(1
), pp. 53
–63
.5.
Tagantsev
, A. K.
, Meunier
, V.
, and Sharma
, P.
, 2009
, “Novel Electromechanical Phenomena at the Nanoscale: Phenomenological Theory and Atomistic Modeling
,” MRS Bull.
, 34
(9
), pp. 643
–647
.6.
Zubko
, P.
, Catalan
, G.
, and Tagantsev
, A. K.
, 2013
, “Flexoelectric Effect in Solids
,” Annu. Rev. Mater. Res.
, 43
(1
), pp. 387
–421
.7.
Yudin
, P. V.
, and Tagantsev
, A. K.
, 2013
, “Fundamentals of Flexoelectricity in Solids
,” Nanotechnology
, 24
(43
), p. 432001
.8.
Nguyen
, T. D.
, Mao
, S.
, Yeh
, Y.-W.
, Purohit
, P. K.
, and McAlpine
, M. C.
, 2013
, “Nanoscale Flexoelectricity
,” Adv. Mater.
, 25
(7
), pp. 946
–974
.9.
Ahmadpoor
, F.
, and Sharma
, P.
, 2013
, “Flexoelectricity in Two-Dimensional Crystalline and Biological Membranes
,” Nanoscale
, 25
(7
), pp. 946
–974
.10.
Dumitrica
, T.
, Landis
, C. M.
, and Yakobson
, B. I.
, 2002
, “Curvature-Induced Polarization in Carbon Nanoshells
,” Chem. Phys. Lett.
, 360
(1
), pp. 182
–188
.11.
Chandratre
, S.
, and Sharma
, P.
, 2012
, “Coaxing Graphene to be Piezoelectric
,” Appl. Phys. Lett.
, 100
(2
), p. 023114
.12.
Kalinin
, S. V.
, and Meunier
, V.
, 2008
, “Electronic Flexoelectricity in Low-Dimensional Systems
,” Phys. Rev. B
, 77
(3
), p. 033403
.13.
Zelisko
, M.
, Hanlumyuang
, Y.
, Yang
, S.
, Liu
, Y.
, Lei
, C.
, Li
, J.
, Pulickel
, M.
, Ajayan
, P. M.
, and Sharma
, P.
, 2014
, “Anomalous Piezoelectricity in Two-Dimensional Graphene Nitride Nano Sheets
,” Nat. Commun.
, 5
, p. 4284
.14.
Naumov
, I.
, Bratkovsky
, A. M.
, and Ranjan
, V.
, 2009
, “Unusual Flexoelectric Effect in Two-Dimensional Noncentrosymmetric sp2-Bonded Crystals
,” Phys. Rev. Lett.
, 102
(21
), p. 217601
.15.
Duerloo
, K.-A. N.
, and Reed
, E. J.
, 2013
, “Flexural Electromechanical Coupling: A Nanoscale Emergent Property of Boron Nitride Bilayers
,” Nano Lett.
, 13
(4
), pp. 1681
–1686
.16.
Petrov
, A. G.
, 2002
, “Flexoelectricity of Model and Living Membranes
,” Biochim. Biophys. Acta
, 1561
(1
), pp. 1
–25
.17.
Fu
, J. Y.
, Zhu
, W.
, Li
, N.
, and Cross
, L. E.
, 2006
, “Experimental Studies of the Converse Flexoelectric Effect Induced by Inhomogeneous Electric Field in a Barium Strontium Titanate Composition
,” J. Appl. Phys.
, 100
(2
), p. 024112
.18.
Fu
, J. Y.
, Zhu
, W.
, Li
, N.
, Smith
, N. B.
, and Cross
, L. E.
, 2007
, “Gradient Scaling Phenomenon in Microsize Flexoelectric Piezoelectric Composites
,” Appl. Phys. Lett.
, 91
(18
), p. 182910
.19.
Ma
, W.
, and Cross
, L. E.
, 2002
, “Flexoelectric Polarization of Barium Strontium Titanate in the Paraelectric State
,” Appl. Phys. Lett.
, 81
(18
), pp. 3440
–3442
.20.
Zubko
, G. P.
, Catalan
, A. R.
, Buckley
, P.
, Welche
, L.
, and Scott
, J. F.
, 2007
, “Strain-Gradient Induced Polarization in SrTiO3 Single Crystals
,” Phys. Rev. Lett.
, 99
(16
), p. 167601
.21.
Ma
, W.
, and Cross
, L. E.
, 2003
, “Strain-Gradient Induced Electric Polarization in Lead Zirconate Titanate Ceramics
,” Appl. Phys. Lett.
, 82
(19
), pp. 3923
–3925
.22.
Chu
, B.
, and Salem
, D. R.
, 2012
, “Flexoelectricity in Several Thermoplastic and Thermosetting Polymers
,” Appl. Phys. Lett.
, 101
(10
), p. 103905
.23.
Baskaran
, S.
, He
, X.
, Chen
, Q.
, and Fu
, J. Y.
, 2011
, “Experimental Studies on the Direct Flexoelectric Effect in α-Phase Polyvinylidene Fluoride Films
,” Appl. Phys. Lett.
, 98
(24
), p. 242901
.24.
Baskaran
, S.
, He
, X.
, Wang
, Y.
, and Fu
, J. Y.
, 2012
, “Strain Gradient Induced Electric Polarization in α-Phase Polyvinylidene Fluoride Films Under Bending Conditions
,” J. Appl. Phys.
, 111
(1
), p. 014109
.25.
Sharma
, N. D.
, Landis
, C. M.
, and Sharma
, P.
, 2010
, “Piezoelectric Thin-Film Superlattices Without Using Piezoelectric Materials
,” J. Appl. Phys.
, 108
(2
), p. 024304
.26.
Deng
, Q.
, Liu
, L.
, and Sharma
, P.
, 2014
, “Flexoelectricity in Soft Materials and Biological Membranes
,” J. Mech. Phys. Solids
, 62
, pp. 209
–227
.27.
Deng
, Q.
, Liu
, L.
, and Sharma
, P.
, 2014
, “Electrets in Soft Materials: Nonlinearity, Size Effects, and Giant Electromechanical Coupling
,” Phys. Rev. E
, 90
(1
), p. 012603
.28.
Deng
, Q.
, Kammoun
, M.
, Erturk
, A.
, and Sharma
, P.
, 2014
, “Nanoscale Flexoelectric Energy Harvesting
,” Int. J. Solids Struct.
, 51
(18
), pp. 3218
–3225
.29.
Sharma
, N. D.
, Maranganti
, R.
, and Sharma
, P.
, 2007
, “On the Possibility of Piezoelectric Nanocomposites Without Using Piezoelectric Materials
,” J. Mech. Phys. Solids
, 55
(18
), p. 2328
.30.
Sodano
, H. A.
, Inman
, D. J.
, and Park
, G.
, 2004
, “A Review of Power Harvesting From Vibration Using Piezoelectric Materials
,” Shock Vib. Dig.
, 36
(3
), pp. 197
–206
.31.
Jiang
, X.
, Huang
, W.
, and Zhang
, S.
, 2013
, “Flexoelectric Nano-Generator: Materials, Structures and Devices
,” Nano Energy
, 2
(6
), pp. 1079
–1092
.32.
Majdoub
, M. S.
, Sharma
, P.
, and Cagin
, T.
, 2008
, “Dramatic Enhancement in Energy Harvesting for a Narrow Range of Dimensions in Piezoelectric Nanostructures
,” Phys. Rev. B
, 78
(12
), p. 121407
.33.
Majdoub
, M. S.
, Sharma
, P.
, and Cagin
, T.
, 2009
, “Erratum: Dramatic Enhancement in Energy Harvesting for a Narrow Range of Dimensions in Piezoelectric Nanostructures [Phys. Rev. B, 78, 121407 (R)(2008)]
,” Phys. Rev. B
, 79
(15
), p. 159901
.34.
Mbarki
, R.
, Baccam
, N.
, Dayal
, K.
, and Sharma
, P.
, 2014
, “Piezoelectricity Above the Curie Temperature? Combining Flexoelectricity and Functional Grading to Enable High-Temperature Electromechanical Coupling
,” Appl. Phys. Lett.
, 104
(12
), p. 122904
.35.
Catalan
, G.
, Lubk
, A.
, Vlooswijk
, A. H. G.
, Snoeck
, E.
, Magen
, C.
, Janssens
, A.
, Rispens
, G.
, Rijnders
, G.
, Blank
, D. H. A.
, and Noheda
, B.
, 2010
, “Flexoelectric Rotation of Polarization in Ferroelectric Thin Films
,” Nat. Mater.
, 23
(1
), p. 963
.36.
Gharbi
, M.
, Sun
, Z. H.
, Sharma
, P.
, and White
, K.
, 2009
, “The Origins of Electromechanical Indentation Size Effect in Ferroelectrics
,” Appl. Phys. Lett.
, 95
(14
), p. 142901
.37.
Abdollahi
, A.
, Peco
, C.
, Millán
, D.
, Arroyo
, M.
, Catalan
, G.
, and Arias
, I.
, 2015
, “Fracture Toughening and Toughness Asymmetry Induced by Flexoelectricity
,” Phys. Rev. B
, 92
(9
), p. 094101
.38.
Mao
, S.
, and Purohit
, P.
, 2015
, “Defects in Flexoelectric Solids
,” J. Mech. Phys. Solids
, 84
, p. 95
.39.
Bhaskar
, U. K.
, Banerjee
, N.
, Abdollahi
, A.
, Solanas
, E.
, Rijnders
, G.
, and Catalan
, G.
, 2016
, “Flexoelectric MEMS: Towards an Electromechanical Strain Diode
,” Nanoscale
, 8
(3
), pp. 1293
–1298
.40.
Bhaskar
, U. K.
, Banerjee
, N.
, Abdollahi
, A.
, Wang
, Z.
, Schlom
, D. G.
, Rijnders
, G.
, and Catalan
, G.
, 2015
, “A Flexoelectric Microelectromechanical System on Silicon
,” Nat. Nanotechnol.
(in press).41.
Wang
, Z.
, Zhang
, X. X.
, Wang
, X.
, Yue
, W.
, Li
, J.
, Miao
, J.
, and Zhu
, W.
, 2013
, “Giant Flexoelectric Polarization in a Micromachined Ferroelectric Diaphragm
,” Adv. Funct. Mater.
, 23
(1
), pp. 124
–132
.42.
Liu
, L. P.
, and Sharma
, P.
, 2013
, “Flexoelectricity and Thermal Fluctuations of Lipid Bilayer Membranes: Renormalization of Flexoelectric, Dielectric, and Elastic Properties
,” Phys. Rev. E
, 87
(3
), p. 032715
.43.
Petrov
, A. G.
, and Mircevova
, L.
, 1986
, “Is Flexoelectricity the Coupling Factor Between Chemical Energy and Osmotic Work in the Pump? A Model of Pump
,” Gen. Physiol. Biophys.
, 5
(4
), pp. 391
–403
.44.
Petrov
, A. G.
, 1975
, “Flexoelectric Model for Active Transport
,” Physical and Chemical Bases of Biological Information Transfer
, Springer
, New York
, pp. 111
–125
.45.
Rey
, A. D.
, 2006
, “Liquid Crystal Model of Membrane Flexoelectricity
,” Phys. Rev. E
, 74
(1
), p. 011710
.46.
Gao
, L.-T.
, Feng
, X.-Q.
, Yin
, Y.-J.
, and Gao
, H.
, 2008
, “An Electromechanical Liquid Crystal Model of Vesicles
,” J. Mech. Phys. Solids
, 56
(9
), pp. 2844
–2862
.47.
Zhang
, P.-C.
, Keleshian
, A. M.
, and Sachs
, F.
, 2001
, “Voltage-Induced Membrane Movement
,” Nature
, 413
(6854
), pp. 428
–432
.48.
Reichenbach
, T.
, and Hudspeth
, A. J.
, 2014
, “The Physics of Hearing: Fluid Mechanics and the Active Process of the Inner Ear
,” Rep. Prog. Phys.
, 77
(7
), p. 076601
.49.
Sachs
, F.
, Brownell
, W. E.
, and Petrov
, A. G.
, 2009
, “Membrane Electromechanics in Biology, With a Focus on Hearing
,” MRS Bull.
, 34
(09), pp. 665
–670
.50.
Raphael
, R. M.
, Popel
, A. S.
, and Brownell
, W. E.
, 2000
, “A Membrane Bending Model of Outer Hair Cell Electromotility
,” Biophys. J.
, 78
(6
), pp. 2844
–2862
.51.
Spector
, A. A.
, Deo
, N.
, Grosh
, K.
, Ratnanather
, J. T.
, and Raphael
, R. M.
, 2006
, “Electromechanical Models of the Outer Hair Cell Composite Membrane
,” J. Membr. Biol.
, 209
(2–3
), pp. 135
–152
.52.
Breneman
, K. D.
, and Rabbitt
, R. D.
, 2009
, “Piezo- and Flexoelectric Membrane Materials Underlie Fast Biological Motors in the Inner Ear
,” MRS Proc.
, 1186
, p. 1186-JJ06-04
.53.
Brownell
, W. E.
, Spector
, A. A.
, Raphael
, R. M.
, and Popel
, A. S.
, 2001
, “Micro-and Nanomechanics of the Cochlear Outer Hair Cell
,” Annu. Rev. Biomed. Eng.
, 3
(1
), pp. 169
–194
.54.
Breneman
, K. D.
, William
, E. B.
, and Richard
, D. R.
, 2009
, “Hair Cell Bundles: Flexoelectric Motors of the Inner Ear
,” PLoS One
, 4
(4
), p. e5201
.55.
Abou-Dakka
, M.
, Herrera-Valencia
, E. E.
, and Rey
, A. D.
, 2012
, “Linear Oscillatory Dynamics of Flexoelectric Membranes Embedded in Viscoelastic Media With Applications to Outer Hair Cells
,” J. Non-Newtonian Fluid Mech.
, 185
, pp. 1
–17
.56.
Stengel
, M.
, 2013
, “Flexoelectricity From Density-Functional Perturbation Theory
,” Phys. Rev. B
, 88
(17
), p. 174106
.57.
Derzhanski
, A.
, Petrov
, A. G.
, Todorov
, A. T.
, and Hristova
, K.
, 1990
, “Flexoelectricity of Lipid Bilayers
,” Liq. Cryst.
, 7
(3
), pp. 439
–449
.58.
Petrov
, A. G.
, Ramsey
, R. L.
, and Usherwood
, P. N. R.
, 1989
, “Curvature-Electric Effects in Artificial and Natural Membranes Studied Using Patch-Clamp Techniques
,” Eur. Biophys. J.
, 17
(1
), pp. 13
–17
.59.
Petrov
, A. G.
, and Sokolov
, V. S.
, 1986
, “Curvature-Electric Effect in Black Lipid Membranes
,” Eur. Biophys. J.
, 13
(3
), pp. 139
–155
.60.
Petrov
, A. G.
, Miller
, B. A.
, Hristova
, K.
, and Usherwood
, P. N. R.
, 1993
, “Flexoelectric Effects in Model and Native Membranes Containing Ion Channels
,” Eur. Biophys. J.
, 22
(4
), pp. 289
–300
.61.
Todorov
, A. T.
, Petrov
, A. G.
, and Fendler
, J. H.
, 1994
, “First Observation of the Converse Flexoelectric Effect in Bilayer Lipid Membranes
,” J. Phys. Chem.
, 98
(12
), pp. 3076
–3079
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