Surface detection in nanoindentation of soft polymers

Abstract

In this work, we performed nanoindentation studies on polymers with different moduli in the range of several millipascals up to several gigapascals. The focus was on the initial contact identification during indentation testing. Surface-detection methods using quasi-static loading as well as methods employing the dynamic forces associated with the continuous stiffness measurement technique were compared regarding their practicability and accuracy for the testing of polymeric materials. For the most compliant material with a modulus of 1 MPa, where contact identification is most critical, we used load-displacement curves obtained from finite element modeling analysis as a reference for the evaluation of experimental techniques. The results show how crucial the precise surface detection is for achieving accurate indentation results, especially for compliant materials. Further, we found that surface detection by means of dynamic testing provides mechanical-property values of higher accuracy for all polymers used in this study. This was due to smaller errors in surface detection, thus avoiding a significant underestimation of the contact area.

This is a preview of subscription content, access via your institution.

FIG. 1
FIG. 2
FIG. 3
FIG. 4
FIG. 5
FIG. 6
FIG. 7
FIG. 8
TABLE I.
TABLE II.
FIG. 9
FIG. 10
FIG. 11
FIG. 12
FIG. 13
FIG. 14
TABLE III.

References

  1. 1

    K. Herrmann, P. Strobel A. Stibler: A new hardness testing method for very soft elastomers. Materialprüfung. 44, 83 2003

    Google Scholar 

  2. 2

    N. Barbakadze, S. Enders, S. Gorb E. Arzt: Local mechanical properties of the head articulation cuticle in the beetle Pachnoda marginata (Coleoptera, Scarabaeidae). J. Exp. Biol. 209(4), 722 2006

    CAS  Article  Google Scholar 

  3. 3

    M.R. VanLandingham, J.S. Villarrubia, W.F. Guthrie G.F. Meyers: Nanoindentation of polymers: An overview., Proceedings of 220th American Chemical Society National Meeting, Macromolecular Symposia (Washington, DC, 2001), p. 15

  4. 4

    S.A. Hayes, A.A. Goruppa F.R. Jones: Dynamic nanoindentation as a tool for the examination of polymeric materials. J. Mater. Res. 19, 3298 2004

    CAS  Article  Google Scholar 

  5. 5

    G.M. Odegard, T.S. Gates H.M. Herring: Characterization of viscoelastic properties of polymeric materials through nanoindentation. Exp. Mech. 45, 130 2005

    Article  Google Scholar 

  6. 6

    Z. Li, J.C.M. Brokken-Zijp G. de With: Determination of elastic moduli of silicone rubber coatings and films using depth-sensing indentation. Polymer 45, 5403 2004

    CAS  Article  Google Scholar 

  7. 7

    C.C. White, M.R. VanLandingham, P.L. Drzal, N-K. Chang S-H. Chang: Viscoelastic characterization of polymers using instrumented indentation: II. Dynamic testing. J Polym. Sci., Part B: Polym. Phys. 43, 1812 2005

    CAS  Article  Google Scholar 

  8. 8

    J-L. Loubet, B.N. Lucas W.C. Oliver: Some measurements of viscoelastic properties with the help of nanoindentation, NIST Special Publication 896, Proceedings of International Workshop on Instrumented Indentation (San Diego, CA, 1995), p. 31

  9. 9

    J-L. Loubet, W.C. Oliver B.N. Lucas: Measurement of the loss tangent of low-density polyethylene with a nanoindetation technique. J. Mater. Res. 15, 1195 2000

    CAS  Article  Google Scholar 

  10. 10

    T. Jamsa, J-Y. Rho, Z. Fan, C.A. Mackay, S.C. Marks Jr. J. Tuukkanen: Mechanical properties in long bones of rat osteoporotic mutations. J. Biomech. 35, 161 2002

    Article  Google Scholar 

  11. 11

    J.L. Cuy, A.B. Mann, K.J. Livi M.F. Teaford: Nanoindentation mapping of the mechanical properties of human molar tooth enamel. Arch. Oral Biol. 47, 281 2002

    CAS  Article  Google Scholar 

  12. 12

    M.E. Dickinson A.B. Mann: Nanomechanics and chemistry of caries-like lesions in dental enamel in Mechanical Properties of Bioinspired and Biological Materials, edited by C. Viney, K. Katti, F.-J. Ulm, and C. Hellmich (Mater. Res. Soc. Symp. Proc. 844, Warrendale, PA, 2005), p. Y9.2

  13. 13

    E.J. Berger, S. Tripathy, K. Vemaganti, Y.M. Kolambkar, H.X. You, K. Courtney: An atomic force indentation study of biomaterial properties, WTC 2005-63244, Proceedings of World Tribology Congress III Washington, DC 2005

  14. 14

    D.M. Ebenstein K.J. Wahl: A comparison of JKR-based methods to analyze quasi-static and dynamic indentation force curves. J. Colloid Interface Sci. 298, 652 2006

    CAS  Article  Google Scholar 

  15. 15

    C.A. Tweedie K.J. van Vliet: On the indentation recovery and fleeting hardness of polymers. J. Mater. Res. 21, 3029 2006

    CAS  Article  Google Scholar 

  16. 16

    Y. Cao, D. Yang W. Soboyejoy: Nanoindentation method for determining the initial contact and adhesion characteristics of soft polydimethylsiloxane. J. Mater. Res. 20, 2004 2005

    CAS  Article  Google Scholar 

  17. 17

    W.C. Oliver G.M. Pharr: An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments. J. Mater. Res. 7, 1564 1992

    CAS  Article  Google Scholar 

  18. 18

    W.C. Oliver G.M. Pharr: Measurement of hardness and elastic modulus by instrumented indentation: Advances in understanding and refinements to methodology. J. Mater. Res. 19, 3 2004

    CAS  Article  Google Scholar 

  19. 19

    Y.T. Cheng C.M. Cheng: Relationship between initial unloading slope, contact depth, and mechanical properties for conical indentation in linear viscoelastic solids. J. Mater. Res. 20, 1046 2005

    CAS  Article  Google Scholar 

  20. 20

    S. Yang, Y-W. Zhang K. Zeng: Analysis of nanoindentation creep for polymeric materials. J. Appl. Phys. 95, 3655 2004

    CAS  Article  Google Scholar 

  21. 21

    B. Tang A.H.W. Ngan: Accurate measurement of tip-sample contact size during nanoindentation of viscoelastic materials. J. Mater. Res. 18, 1141 2003

    CAS  Article  Google Scholar 

  22. 22

    A.C. Fischer-Cripps: A simple phenomenological approach to nanoindentation creep. Mater. Sci. Eng., A 385, 74 2004

    Article  Google Scholar 

  23. 23

    M.L. Oyen R.F. Cook: Load-displacement behaviour during sharp indentation of viscous-elastic-plastic materials. J. Mater. Res. 18, 139 2003

    CAS  Article  Google Scholar 

  24. 24

    A.C. Fischer-Cripps: Multiple-frequency dynamic nanoindentation testing. J. Mater. Res. 19, 2981 2004

    CAS  Article  Google Scholar 

  25. 25

    B.N. Lucas, W.C. Oliver, G.M. Pharr J-L. Loubet: Time dependent deformation during indentation testing in Thin Films: Stresses and Mechanical Properties VI, edited by W.W. Gerberich, H. Gao, J-E. Sundgren, and S.P. Baker (Mater. Res. Soc. Symp. Proc. 436, Pittsburgh, PA, 1997), p. 233

  26. 26

    Nano Instruments Innovation Center MTS Systems Corporation: Nanoindenter XP, Testworks 4 Software for Nanoindentation, Operating Instructions (2004)

    Google Scholar 

  27. 27

    ABAQUS Analysis User’s Manual Version 6.6 Abagus Inc. Providence, RI 2006

  28. 28

    L.J. Guerin: The SU8 homepage, http://www.geocities.com/guerinlj/

  29. 29

    Goodfellow GmbH, Friedberg, Germany, http://www.goodfellow.com

  30. 30

    A.H.W. Ngan B. Tang: Viscoelastic effects during unloading in depth-sensing indentation. J. Mater. Res. 17, 2604 2002

    CAS  Article  Google Scholar 

  31. 31

    G. Feng A.H.W. Ngan: Effects of creep and thermal drift on modulus measurement using depth-sensing indentation. J. Mater. Res. 17, 660 2002

    CAS  Article  Google Scholar 

  32. 32

    J.C. Grunlan, X. Xia, D. Rowenhorst W.W. Gerberich: Preparation and evaluation of tungsten tips relative to diamond for nanoindentation of soft materials. Rev. Sci. Instrum. 72, 2804 2001

    CAS  Article  Google Scholar 

Download references

ACKNOWLEDGMENTS

The authors thank C. Greiner and E. de Souza for providing the SU8 and PDMS samples. We gratefully acknowledge the opportunity to use the facilities of the Institut fuer Statik und Dynamik at the University of Stuttgart for performing the FE simulations, and thank M. Deuschle for his support. For the measurements using the Hysitron indenter, we are grateful to Dr. Z. Burkhard. Helpful discussions with Dr. H. Pfaff are very much appreciated.

Author information

Affiliations

Authors

Corresponding author

Correspondence to Susan Enders.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Deuschle, J., Enders, S. & Arzt, E. Surface detection in nanoindentation of soft polymers. Journal of Materials Research 22, 3107–3119 (2007). https://doi.org/10.1557/JMR.2007.0394

Download citation