Stretchability, Conformability, and Low-Cost Manufacture of Epidermal Sensors

  • Nanshu Lu
  • Shixuan Yang
  • Liu Wang
Part of the Microsystems and Nanosystems book series (MICRONANO)


Epidermal sensors and electronics represent a class of artificial devices whose thickness, mass density, and mechanical stiffness are well-matched with human epidermis. They can be applied as temporary transfer tattoos on the surface of any part of human body for physiological measurements, electrical or thermal stimulation , as well as wireless communications. Except for comfort and wearability, epidermal sensors can offer unprecedented signal quality even under severe skin deformation. This chapter tries to address two fundamental mechanics challenges for epidermal sensors: first, how to predict and improve the stretchability and compliance when epidermal devices are made out of intrinsically brittle and rigid inorganic electronic materials; and second, when laminating on human skin , how to predict and improve the conformability between epidermal devices and the microscopically rough skin surfaces. Since the ideal use of epidermal devices would be one-time, disposable patches, a low cost, high throughput manufacture process called the “cut-and-paste” method is introduced at the end of this chapter.


Epidermal sensors Stretchable Serpentine Conformability Low-cost manufacture 


  1. 1.
    D.H. Kim, R. Ghaffari, N.S. Lu, J.A. Rogers, Flexible and stretchable electronics for bio-integrated devices. Annu. Rev. Biomed. Eng. 14, 113–128 (2012)CrossRefGoogle Scholar
  2. 2.
    D.H. Kim, N.S. Lu, R. Ghaffari, J.A. Rogers, Inorganic semiconductor nanomaterials for flexible and stretchable bio-integrated electronics. NPG Asia Materials 4, e15 (2012)CrossRefGoogle Scholar
  3. 3.
    J. van den Brand, M. de Kok, A. Sridhar, M. Cauwe, R. Verplancke, F. Bossuyt, et al., Flexible and stretchable electronics for wearable healthcare, in Proceedings of the 2014 44th European Solid-State Device Research Conference (Essderc, 2014), pp. 206–209Google Scholar
  4. 4.
    D.H. Kim, N.S. Lu, R. Ma, Y.S. Kim, R.H. Kim, S.D. Wang et al., Epidermal electronics. Science 333, 838–843 (2011)CrossRefGoogle Scholar
  5. 5.
    Z.G. Suo, Mechanics of stretchable electronics and soft machines. MRS Bull. 37, 218–225 (2012)CrossRefGoogle Scholar
  6. 6.
    N. Lu, S. Yang, Mechanics for stretchable sensors. Curr. Opin. Solid State Mater. Sci. in press (2015)Google Scholar
  7. 7.
    J. Song, Mechanics of stretchable electronics. Curr. Opin. Solid State Mater. Sci. 19, 160–170 (2015)CrossRefGoogle Scholar
  8. 8.
    D.H. Kim, N.S. Lu, Y.G. Huang, J.A. Rogers, Materials for stretchable electronics in bioinspired and biointegrated devices. MRS Bull. 37, 226–235 (2012)CrossRefGoogle Scholar
  9. 9.
    W.-H. Yeo, Y.-S. Kim, J. Lee, A. Ameen, L. Shi, M. Li et al., Multifunctional electronics: multifunctional epidermal electronics printed directly onto the skin. Adv. Mater. 25, 2772 (2013)CrossRefGoogle Scholar
  10. 10.
    J.S. Lee, J. Heo, W.K. Lee, Y.G. Lim, Y.H. Kim, K.S. Park, Flexible capacitive electrodes for minimizing motion artifacts in ambulatory electrocardiograms. Sensors 14, 14732–14743 (2014)CrossRefGoogle Scholar
  11. 11.
    J.W. Jeong, M.K. Kim, H.Y. Cheng, W.H. Yeo, X. Huang, Y.H. Liu et al., Capacitive epidermal electronics for electrically safe, long-term electrophysiological measurements. Adv. Healthc. Mater. 3, 642–648 (2014)CrossRefGoogle Scholar
  12. 12.
    J.W. Jeong, W.H. Yeo, A. Akhtar, J.J.S. Norton, Y.J. Kwack, S. Li et al., Materials and optimized designs for human-machine interfaces via epidermal electronics. Adv. Mater. 25, 6839–6846 (2013)CrossRefGoogle Scholar
  13. 13.
    X. Huang, W.H. Yeo, Y. Liu, J.A. Rogers, Epidermal differential impedance sensor for conformal skin hydration monitoring. Biointerphases 7, 52 (2012)CrossRefGoogle Scholar
  14. 14.
    X. Huang, H. Cheng, K. Chen, Y. Zhang, Y. Zhang, Y. Liu et al., Epidermal impedance sensing sheets for precision hydration assessment and spatial mapping. IEEE Trans. Biomed. Eng. 60, 2848–2857 (2013)CrossRefGoogle Scholar
  15. 15.
    X. Huang, Y.H. Liu, H.Y. Cheng, W.J. Shin, J.A. Fan, Z.J. Liu et al., Materials and designs for wireless epidermal sensors of hydration and strain. Adv. Funct. Mater. 24, 3846–3854 (2014)CrossRefGoogle Scholar
  16. 16.
    R.C. Webb, A.P. Bonifas, A. Behnaz, Y.H. Zhang, K.J. Yu, H.Y. Cheng et al., Ultrathin conformal devices for precise and continuous thermal characterization of human skin. Nat. Mater. 12, 938–944 (2013)CrossRefGoogle Scholar
  17. 17.
    M.K. Choi, O.K. Park, C. Choi, S. Qiao, R. Ghaffari, J. Kim, et al., Cephalopod-inspired miniaturized suction cups for smart medical skin. Adv. Healthc. Mater. (2015)Google Scholar
  18. 18.
    D. Son, J. Lee, S. Qiao, R. Ghaffari, J. Kim, J.E. Lee et al., Multifunctional wearable devices for diagnosis and therapy of movement disorders. Nat. Nanotechnol. 9, 397–404 (2014)CrossRefGoogle Scholar
  19. 19.
    J. Kim, M. Lee, H.J. Shim, R. Ghaffari, H.R. Cho, D. Son, et al., Stretchable silicon nanoribbon electronics for skin prosthesis. Nat. Commun. 5 (2014)Google Scholar
  20. 20.
    A.J. Bandodkar, D. Molinnus, O. Mirza, T. Guinovart, J.R. Windmiller, G. Valdes-Ramirez et al., Epidermal tattoo potentiometric sodium sensors with wireless signal transduction for continuous non-invasive sweat monitoring. Biosens. Bioelectron. 54, 603–609 (2014)CrossRefGoogle Scholar
  21. 21.
    W. Jia, A.J. Bandodkar, G. Valdes-Ramirez, J.R. Windmiller, Z. Yang, J. Ramirez et al., Electrochemical tattoo biosensors for real-time noninvasive lactate monitoring in human perspiration. Anal. Chem. 85, 6553–6560 (2013)CrossRefGoogle Scholar
  22. 22.
    C. Dagdeviren, Y. Shi, P. Joe, R. Ghaffari, G. Balooch, K. Usgaonkar, et al., Conformal piezoelectric systems for clinical and experimental characterization of soft tissue biomechanics. Nat. Mater. 14 (2015)Google Scholar
  23. 23.
    J. Kim, A. Banks, H. Cheng, Z. Xie, S. Xu, K.-I. Jang, et al., Epidermal electronics with advanced capabilities in near-field communication. Small (2014)Google Scholar
  24. 24.
    J.A. Fan, W.H. Yeo, Y.W. Su, Y. Hattori, W. Lee, S.Y. Jung, et al., Fractal design concepts for stretchable electronics. Nat. Commun. 5 (2014)Google Scholar
  25. 25.
    D.S. Gray, J. Tien, C.S. Chen, High-conductivity elastomeric electronics. Adv. Mater. 16, 393 (2004)Google Scholar
  26. 26.
    T. Li, Z.G. Suo, S.P. Lacour, S. Wagner, Compliant thin film patterns of stiff materials as platforms for stretchable electronics. J. Mater. Res. 20, 3274–3277 (2005)CrossRefGoogle Scholar
  27. 27.
    D. Brosteaux, F. Axisa, M. Gonzalez, J. Vanfleteren, Design and fabrication of elastic interconnections for stretchable electronic circuits. IEEE Electron Device Lett. 28, 552–554 (2007)CrossRefGoogle Scholar
  28. 28.
    D.H. Kim, J.Z. Song, W.M. Choi, H.S. Kim, R.H. Kim, Z.J. Liu et al., Materials and noncoplanar mesh designs for integrated circuits with linear elastic responses to extreme mechanical deformations. Proc. Natl. Acad. Sci. U.S.A. 105, 18675–18680 (2008)CrossRefGoogle Scholar
  29. 29.
    Y.Y. Hsu, M. Gonzalez, F. Bossuyt, F. Axisa, J. Vanfleteren, I. De Wolf, In situ observations on deformation behavior and stretching-induced failure of fine pitch stretchable interconnect. J. Mater. Res. 24, 3573–3582 (2009)CrossRefGoogle Scholar
  30. 30.
    Y.Y. Hsu, M. Gonzalez, F. Bossuyt, J. Vanfleteren, I. De Wolf, Polyimide-enhanced stretchable interconnects: design, fabrication, and characterization. IEEE Trans. Electron Devices 58, 2680–2688 (2011)CrossRefGoogle Scholar
  31. 31.
    D.H. Kim, N.S. Lu, R. Ghaffari, Y.S. Kim, S.P. Lee, L.Z. Xu et al., Materials for multifunctional balloon catheters with capabilities in cardiac electrophysiological mapping and ablation therapy. Nat. Mater. 10, 316–323 (2011)CrossRefGoogle Scholar
  32. 32.
    S. Xu, Y.H. Zhang, J. Cho, J. Lee, X. Huang, L. Jia, et al., Stretchable batteries with self-similar serpentine interconnects and integrated wireless recharging systems. Nat. Commun. 4 (2013)Google Scholar
  33. 33.
    R.H. Kim, M.H. Bae, D.G. Kim, H.Y. Cheng, B.H. Kim, D.H. Kim et al., Stretchable, transparent graphene interconnects for arrays of microscale inorganic light emitting diodes on rubber substrates. Nano Lett. 11, 3881–3886 (2011)CrossRefGoogle Scholar
  34. 34.
    C.J. Yu, Z. Duan, P.X. Yuan, Y.H. Li, Y.W. Su, X. Zhang et al., Electronically programmable, reversible shape change in two- and three-dimensional hydrogel structures. Adv. Mater. 25, 1541–1546 (2013)CrossRefGoogle Scholar
  35. 35.
    T. Ma, Y. Wang, R. Tang, H. Yu, H. Jiang, Pre-patterned ZnO nanoribbons on soft substrates for stretchable energy harvesting applications. J. Appl. Phys. 113 (2013)Google Scholar
  36. 36.
    G. Lanzara, N. Salowitz, Z.Q. Guo, F.K. Chang, A spider-web-like highly expandable sensor network for multifunctional materials. Adv. Mater. 22, 4643–4648 (2010)CrossRefGoogle Scholar
  37. 37.
    M. Gonzalez, F. Axisa, F. Bossuyt, Y.Y. Hsu, B. Vandevelde, J. Vanfleteren, Design and performance of metal conductors for stretchable electronic circuits. Circuit World 35, 22–29 (2009)CrossRefGoogle Scholar
  38. 38.
    G. Mani, M.D. Feldman, D. Patel, C.M. Agrawal, Coronary stents: a materials perspective. Biomaterials 28, 1689–1710 (2007)CrossRefGoogle Scholar
  39. 39.
    T. Widlund, S. Yang, Y.-Y. Hsu, N. Lu, Stretchability and compliance of freestanding serpentine-shaped ribbons. Int. J. Solids Struct. 51, 4026–4037 (2014)CrossRefGoogle Scholar
  40. 40.
    S. Yang, S. Qiao, N. Lu, Elasticity solutions to freestanding, non-buckling serpentine ribbons. To be submitted (2016)Google Scholar
  41. 41.
    D.H. Kim, R. Ghaffari, N.S. Lu, S.D. Wang, S.P. Lee, H. Keum et al., Electronic sensor and actuator webs for large-area complex geometry cardiac mapping and therapy. Proc. Natl. Acad. Sci. U.S.A. 109, 19910–19915 (2012)CrossRefGoogle Scholar
  42. 42.
    Y.L. Yu, D. Sanchez, N.S. Lu, Work of adhesion/separation between soft elastomers of different mixing ratios. J. Mater. Res. 30, 2702–2712 (2015)CrossRefGoogle Scholar
  43. 43.
    Y.W. Su, J. Wu, Z.C. Fan, K.C. Hwang, J.Z. Song, Y.G. Huang et al., Postbuckling analysis and its application to stretchable electronics. J. Mech. Phys. Solids 60, 487–508 (2012)MathSciNetCrossRefzbMATHGoogle Scholar
  44. 44.
    Y.H. Zhang, S. Xu, H.R. Fu, J. Lee, J. Su, K.C. Hwang et al., Buckling in serpentine microstructures and applications in elastomer-supported ultra-stretchable electronics with high areal coverage. Soft Matter 9, 8062–8070 (2013)CrossRefGoogle Scholar
  45. 45.
    Y. Zhang, H. Fu, Y. Su, S. Xu, H. Cheng, J.A. Fan, et al., Mechanics of ultra-stretchable self-similar serpentine interconnects. Acta Mater. 61, 7816–7827, (2013)Google Scholar
  46. 46.
    Y. Zhang, H. Fu, S. Xu, J.A. Fan, K.-C. Hwang, J. Jiang, et al., A hierarchical computational model for stretchable interconnects with fractal-inspired designs. J. Mech. Phys. Solids, 72, 115–130 (2014)Google Scholar
  47. 47.
    Y.Y. Hsu, M. Gonzalez, F. Bossuyt, F. Axisa, J. Vanfleteren, I. DeWolf, The effect of pitch on deformation behavior and the stretching-induced failure of a polymer-encapsulated stretchable circuit. J. Micromech. Microeng. 20 (2010)Google Scholar
  48. 48.
    Y.Y. Hsu, M. Gonzalez, F. Bossuyt, F. Axisa, J. Vanfleteren, B. Vandevelde et al., Design and analysis of a novel fine pitch and highly stretchable interconnect. Microelectron. Int. 27, 33–38 (2010)CrossRefGoogle Scholar
  49. 49.
    M. Gonzalez, B. Vandevelde, W. Christiaens, Y.Y. Hsu, F. Iker, F. Bossuyt et al., Design and implementation of flexible and stretchable systems. Microelectron. Reliab. 51, 1069–1076 (2011)CrossRefGoogle Scholar
  50. 50.
    S. Yang, B. Su, G. Bitar, N. Lu, Stretchability of indium tin oxide (ITO) serpentine thin films supported by Kapton substrates. Int. J. Fract. 190, 99–110, (2014)Google Scholar
  51. 51.
    S. Yang, E. Ng, N. Lu, Indium tin oxide (ito) serpentine ribbons on soft substrates stretched beyond 100%. Extreme Mech. Lett. 2, 37–45 (2015)CrossRefGoogle Scholar
  52. 52.
    U. Betz, M.K. Olsson, J. Marthy, M.F. Escola, F. Atamny, Thin films engineering of indium tin oxide: Large area flat panel displays application. Surf. Coat. Technol. 200, 5751–5759 (2006)CrossRefGoogle Scholar
  53. 53.
    H. Schmidt, H. Flugge, T. Winkler, T. Bulow, T. Riedl, W. Kowalsky, Efficient semitransparent inverted organic solar cells with indium tin oxide top electrode. Appl. Phys. Lett. 94 (2009)Google Scholar
  54. 54.
    Y. Leterrier, L. Medico, F. Demarco, J.A.E. Manson, U. Betz, M.F. Escola et al., Mechanical integrity of transparent conductive oxide films for flexible polymer-based displays. Thin Solid Films 460, 156–166 (2004)CrossRefGoogle Scholar
  55. 55.
    N.S. Lu, X. Wang, Z. Suo, J. Vlassak, Metal films on polymer substrates stretched beyond 50%. Appl. Phys. Lett. 91, 221909 (2007)Google Scholar
  56. 56.
    R.M. Niu, G. Liu, C. Wang, G. Zhang, X.D. Ding, J. Sun, Thickness dependent critical strain in submicron Cu films adherent to polymer substrate. Appl. Phys. Lett. 90 (2007)Google Scholar
  57. 57.
    N.S. Lu, Z.G. Suo, J.J. Vlassak, The effect of film thickness on the failure strain of polymer-supported metal films. Acta Mater. 58, 1679–1687 (2010)CrossRefGoogle Scholar
  58. 58.
    S. Yang, Y.C. Chen, L. Nicolini, P. Pasupathy, J. Sacks, S. Becky et al., “Cut-and-paste” manufacture of multiparametric epidermal sensor systems. Adv. Mater. (2015). doi: 10.1002/adma.201502386 Google Scholar
  59. 59.
    M.D. Casper, A.Ö. Gözen, M.D. Dickey, J. Genzer, J.-P. Maria, Surface wrinkling by chemical modification of poly(dimethylsiloxane)-based networks during sputtering. Soft Matter 9, 7797 (2013)CrossRefGoogle Scholar
  60. 60.
    S. Choi, J. Park, W. Hyun, J. Kim, J. Kim, Y.B. Lee et al., Stretchable Heater Using Ligand-Exchanged Silver Nanowire Nanocomposite for Wearable Articular Thermotherapy. ACS Nano 9, 6626–6633 (2015)CrossRefGoogle Scholar
  61. 61.
    S. Hong, H. Lee, J. Lee, J. Kwon, S. Han, Y.D. Suh et al., Highly stretchable and transparent metal nanowire heater for wearable electronics applications. Adv. Mater. 27, 4744–4751 (2015)CrossRefGoogle Scholar
  62. 62.
    X. Huang, Y.H. Liu, K.L. Chen, W.J. Shin, C.J. Lu, G.W. Kong et al., Stretchable, wireless sensors and functional substrates for epidermal characterization of sweat. Small 10, 3083–3090 (2014)CrossRefGoogle Scholar
  63. 63.
    Z.Y. Huang, W. Hong, Z. Suo, Nonlinear analyses of wrinkles in a film bonded to a compliant substrate. J. Mech. Phys. Solids 53, 2101–2118 (2005)MathSciNetCrossRefzbMATHGoogle Scholar
  64. 64.
    J. Xiao, A. Carlson, Z.J. Liu, Y. Huang, J.A. Rogers, Analytical and experimental studies of the mechanics of deformation in a solid with a wavy surface profile. J. Appl. Mech. 77, 011003 (2009)CrossRefGoogle Scholar
  65. 65.
    L. Wang, N. Lu, Conformability of a thin elastic membrane laminated on a soft substrate with slightly wavy surface. J. Appl. Mech. under review (2016)Google Scholar
  66. 66.
    S. Qiao, J.-B. Gratadour, L. Wang, N. Lu, Conformability of a thin elastic membrane laminated on a rigid substrate with corrugated surfaceGoogle Scholar
  67. 67.
    T.J. Wagner, D. Vella, The sensitivity of graphene “snap-through” to substrate geometry. Appl. Phys. Lett. 100, 233111 (2012)CrossRefGoogle Scholar
  68. 68.
    S. Scharfenberg, N. Mansukhani, C. Chialvo, R.L. Weaver, N. Mason, Observation of a snap-through instability in graphene. Appl. Phys. Lett. 100, 021910 (2012)CrossRefGoogle Scholar
  69. 69.
    N. Lu, D.H. Kim, Flexible and stretchable electronics paving the way for soft robotics. Soft Robotics 1, 53–62 (2013)CrossRefGoogle Scholar
  70. 70.
    M.A. Pacheco, C.L. Marshall, Review of dimethyl carbonate (DMC) manufacture and its characteristics as a fuel additive. Energy Fuels 11, 2–29 (1997)Google Scholar

Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  1. 1.Department of Aerospace Engineering and Engineering MechanicsCenter for Mechanics of Solids, Structures, and Materials, University of Texas at AustinAustinUSA
  2. 2.Department of Biomedical EngineeringUniversity of Texas at AustinAustinUSA

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