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Advances in Condensed Matter Physics
Volume 2015, Article ID 391579, 20 pages
http://dx.doi.org/10.1155/2015/391579
Review Article

Indentation Depth Dependent Mechanical Behavior in Polymers

Department of Mechanical Engineering, University of Wyoming, 1000 E. University Avenue, Laramie, WY 82071, USA

Received 20 April 2015; Accepted 9 July 2015

Academic Editor: Victor V. Moshchalkov

Copyright © 2015 Farid Alisafaei and Chung-Souk Han. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Linked References

  1. W. D. Nix and H. Gao, “Indentation size effects in crystalline materials: a law for strain gradient plasticity,” Journal of the Mechanics and Physics of Solids, vol. 46, no. 3, pp. 411–425, 1998. View at Publisher · View at Google Scholar · View at Scopus
  2. J. G. Swadener, E. P. George, and G. M. Pharr, “The correlation of the indentation size effect measured with indenters of various shapes,” Journal of the Mechanics and Physics of Solids, vol. 50, no. 4, pp. 681–694, 2002. View at Publisher · View at Google Scholar · View at Scopus
  3. R. K. Abu Al-Rub, “Prediction of micro and nanoindentation size effect from conical or pyramidal indentation,” Mechanics of Materials, vol. 39, no. 8, pp. 787–802, 2007. View at Publisher · View at Google Scholar · View at Scopus
  4. G. Feng and W. D. Nix, “Indentation size effect in MgO,” Scripta Materialia, vol. 51, no. 6, pp. 599–603, 2004. View at Publisher · View at Google Scholar · View at Scopus
  5. A. A. Elmustafa and D. S. Stone, “Indentation size effect in polycrystalline F.C.C. metals,” Acta Materialia, vol. 50, no. 14, pp. 3641–3650, 2002. View at Publisher · View at Google Scholar · View at Scopus
  6. R. K. Abu Al-Rub and G. Z. Voyiadjis, “Analytical and experimental determination of the material intrinsic length scale of strain gradient plasticity theory from micro- and nano-indentation experiments,” International Journal of Plasticity, vol. 20, no. 6, pp. 1139–1182, 2004. View at Publisher · View at Google Scholar · View at Scopus
  7. Q. Ma and D. R. Clarke, “Size dependent hardness of silver single crystals,” Journal of Materials Research, vol. 10, no. 4, pp. 853–863, 1995. View at Publisher · View at Google Scholar · View at Scopus
  8. C. Motz, T. Schöberl, and R. Pippan, “Mechanical properties of micro-sized copper bending beams machined by the focused ion beam technique,” Acta Materialia, vol. 53, no. 15, pp. 4269–4279, 2005. View at Publisher · View at Google Scholar · View at Scopus
  9. N. A. Fleck, G. M. Muller, M. F. Ashby, and J. W. Hutchinson, “Strain gradient plasticity: theory and experiment,” Acta Metallurgica et Materialia, vol. 42, no. 2, pp. 475–487, 1994. View at Publisher · View at Google Scholar · View at Scopus
  10. L. Tsagrakis and E. C. Aifantis, “Recent developments in gradient plasticity. Part I. Formulation and size Effects,” Journal of Engineering Materials and Technology, vol. 124, no. 3, pp. 352–357, 2002. View at Publisher · View at Google Scholar · View at Scopus
  11. M. B. Taylor, H. M. Zbib, and M. A. Khaleel, “Damage and size effect during superplastic deformation,” International Journal of Plasticity, vol. 18, no. 3, pp. 415–442, 2002. View at Publisher · View at Google Scholar · View at Scopus
  12. Y. Cao, S. Allameh, D. Nankivil, S. Sethiaraj, T. Otiti, and W. Soboyejo, “Nanoindentation measurements of the mechanical properties of polycrystalline Au and Ag thin films on silicon substrates: effects of grain size and film thickness,” Materials Science and Engineering A, vol. 427, no. 1-2, pp. 232–240, 2006. View at Publisher · View at Google Scholar · View at Scopus
  13. Y. W. Yan, L. Geng, and A. B. Li, “Experimental and numerical studies of the effect of particle size on the deformation behavior of the metal matrix composites,” Materials Science and Engineering A, vol. 448, no. 1-2, pp. 315–325, 2007. View at Publisher · View at Google Scholar · View at Scopus
  14. Z. Xue, Y. Huang, and M. Li, “Particle size effect in metallic materials: a study by the theory of mechanism-based strain gradient plasticity,” Acta Materialia, vol. 50, no. 1, pp. 149–160, 2002. View at Publisher · View at Google Scholar · View at Scopus
  15. B. J. Briscoe, L. Fiori, and E. Pelillo, “Nano-indentation of polymeric surfaces,” Journal of Physics D: Applied Physics, vol. 31, no. 19, pp. 2395–2405, 1998. View at Publisher · View at Google Scholar · View at Scopus
  16. A. C. M. Chong and D. C. C. Lam, “Strain gradient plasticity effect in indentation hardness of polymers,” Journal of Materials Research, vol. 14, no. 10, pp. 4103–4110, 1999. View at Publisher · View at Google Scholar · View at Scopus
  17. D. C. C. Lam, F. Yang, A. C. M. Chong, J. Wang, and P. Tong, “Experiments and theory in strain gradient elasticity,” Journal of the Mechanics and Physics of Solids, vol. 51, no. 8, pp. 1477–1508, 2003. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at Scopus
  18. A. W. McFarland and J. S. Colton, “Role of material microstructure in plate stiffness with relevance to microcantilever sensors,” Journal of Micromechanics and Microengineering, vol. 15, no. 5, pp. 1060–1067, 2005. View at Publisher · View at Google Scholar · View at Scopus
  19. A. Arinstein, M. Burman, O. Gendelman, and E. Zussman, “Effect of supramolecular structure on polymer nanofibre elasticity,” Nature Nanotechnology, vol. 2, no. 1, pp. 59–62, 2007. View at Publisher · View at Google Scholar · View at Scopus
  20. L. Sun, R. P. S. Han, J. Wang, and C. T. Lim, “Modeling the size-dependent elastic properties of polymeric nanofibers,” Nanotechnology, vol. 19, no. 45, Article ID 455706, 2008. View at Publisher · View at Google Scholar · View at Scopus
  21. S.-Y. Fu, X.-Q. Feng, B. Lauke, and Y.-W. Mai, “Effects of particle size, particle/matrix interface adhesion and particle loading on mechanical properties of particulate-polymer composites,” Composites Part B: Engineering, vol. 39, no. 6, pp. 933–961, 2008. View at Publisher · View at Google Scholar · View at Scopus
  22. D. C. C. Lam and A. C. M. Chong, “Indentation model and strain gradient plasticity law for glassy polymers,” Journal of Materials Research, vol. 14, no. 9, pp. 3784–3788, 1999. View at Publisher · View at Google Scholar · View at Scopus
  23. D. C. C. Lam and A. C. M. Chong, “Effect of cross-link density on strain gradient plasticity in epoxy,” Materials Science and Engineering: A, vol. 281, no. 1-2, pp. 156–161, 2000. View at Publisher · View at Google Scholar · View at Scopus
  24. D. C. C. Lam and A. C. M. Chong, “Characterization and modeling of specific strain gradient modulus of epoxy,” Journal of Materials Research, vol. 16, no. 2, pp. 558–563, 2001. View at Publisher · View at Google Scholar · View at Scopus
  25. F. Alisafaei, C.-S. Han, and N. Lakhera, “Characterization of indentation size effects in epoxy,” Polymer Testing, vol. 40, pp. 70–75, 2014. View at Publisher · View at Google Scholar · View at Scopus
  26. A. K. Dutta, D. Penumadu, and B. Files, “Nanoindentation testing for evaluating modulus and hardness of single-walled carbon nanotube–reinforced epoxy composites,” Journal of Materials Research, vol. 19, no. 1, pp. 158–164, 2004. View at Publisher · View at Google Scholar · View at Scopus
  27. M. Sánchez, J. Rams, M. Campo, A. Jiménez-Suárez, and A. Ureña, “Characterization of carbon nanofiber/epoxy nanocomposites by the nanoindentation technique,” Composites Part B: Engineering, vol. 42, no. 4, pp. 638–644, 2011. View at Publisher · View at Google Scholar · View at Scopus
  28. F. J. B. Calleja, A. Flores, and G. H. Michler, “Microindentation studies at the near surface of glassy polymers: influence of molecular weight,” Journal of Applied Polymer Science, vol. 93, no. 4, pp. 1951–1956, 2004. View at Publisher · View at Google Scholar · View at Scopus
  29. G. Z. Voyiadjis, A. Shojaei, and N. Mozaffari, “Strain gradient plasticity for amorphous and crystalline polymers with application to micro- and nano-scale deformation analysis,” Polymer, vol. 55, no. 16, pp. 4182–4198, 2014. View at Publisher · View at Google Scholar · View at Scopus
  30. C. A. Charitidis, “Nanoscale deformation and nanomechanical properties of polydimethylsiloxane (PDMS),” Industrial & Engineering Chemistry Research, vol. 50, no. 2, pp. 565–570, 2011. View at Publisher · View at Google Scholar · View at Scopus
  31. C. Charitidis, “Nanoscale deformation and nanomechanical properties of soft matter study cases: polydimethylsiloxane, cells and tissues,” ISRN Nanotechnology, vol. 2011, Article ID 719512, 13 pages, 2011. View at Publisher · View at Google Scholar
  32. E. P. Koumoulos, P. Jagdale, I. A. Kartsonakis, M. Giorcelli, A. Tagliaferro, and C. A. Charitidis, “Carbon nanotube/polymer nanocomposites: a study on mechanical integrity through nanoindentation,” Polymer Composites, 2014. View at Publisher · View at Google Scholar · View at Scopus
  33. F. Alisafaei, C.-S. Han, and S. H. R. Sanei, “On the time and indentation depth dependence of hardness, dissipation and stiffness in polydimethylsiloxane,” Polymer Testing, vol. 32, no. 7, pp. 1220–1228, 2013. View at Publisher · View at Google Scholar · View at Scopus
  34. Y. Y. Lim and M. M. Chaudhri, “Indentation of elastic solids with a rigid Vickers pyramidal indenter,” Mechanics of Materials, vol. 38, no. 12, pp. 1213–1228, 2006. View at Publisher · View at Google Scholar · View at Scopus
  35. A. J. Wrucke, C.-S. Han, and P. Majumdar, “Indentation size effect of multiple orders of magnitude in polydimethylsiloxane,” Journal of Applied Polymer Science, vol. 128, no. 1, pp. 258–264, 2013. View at Publisher · View at Google Scholar · View at Scopus
  36. T.-Y. Zhang and W.-H. Xu, “Surface effects on nanoindentation,” Journal of Materials Research, vol. 17, no. 7, pp. 1715–1720, 2002. View at Publisher · View at Google Scholar · View at Scopus
  37. W.-H. Xu, Z.-Y. Xiao, and T.-Y. Zhang, “Mechanical properties of silicone elastomer on temperature in biomaterial application,” Materials Letters, vol. 59, no. 17, pp. 2153–2155, 2005. View at Publisher · View at Google Scholar · View at Scopus
  38. R. V. S. Tatiraju and C.-S. Han, “Rate dependence of indentation size effects in filled silicone rubber,” Journal of Mechanics of Materials and Structures, vol. 5, no. 2, pp. 277–288, 2010. View at Publisher · View at Google Scholar · View at Scopus
  39. L. Shen, T. Liu, and P. Lv, “Polishing effect on nanoindentation behavior of nylon 66 and its nanocomposites,” Polymer Testing, vol. 24, no. 6, pp. 746–749, 2005. View at Publisher · View at Google Scholar · View at Scopus
  40. Y. C. Lu, D. C. Jones, G. P. Tandon, S. Putthanarat, and G. A. Schoeppner, “High temperature nanoindentation of PMR-15 polyimide,” Experimental Mechanics, vol. 50, no. 4, pp. 491–499, 2010. View at Publisher · View at Google Scholar · View at Scopus
  41. R. Seltzer, J.-K. Kim, and Y.-W. Mai, “Elevated temperature nanoindentation behaviour of polyamide 6,” Polymer International, vol. 60, no. 12, pp. 1753–1761, 2011. View at Publisher · View at Google Scholar · View at Scopus
  42. J. F. Nye, “Some geometrical relations in dislocated crystals,” Acta Metallurgica, vol. 1, no. 2, pp. 153–162, 1953. View at Publisher · View at Google Scholar · View at Scopus
  43. A. Arsenlis and D. M. Parks, “Crystallographic aspects of geometrically-necessary and statistically-stored dislocation density,” Acta Materialia, vol. 47, no. 5, pp. 1597–1611, 1999. View at Publisher · View at Google Scholar · View at Scopus
  44. N. A. Fleck and J. W. Hutchinson, “A phenomenological theory for strain gradient effects in plasticity,” Journal of the Mechanics and Physics of Solids, vol. 41, no. 12, pp. 1825–1857, 1993. View at Publisher · View at Google Scholar · View at MathSciNet · View at Scopus
  45. H. Gao, Y. Huang, W. D. Nix, and J. W. Hutchinson, “Mechanism-based strain gradient plasticity—I. Theory,” Journal of the Mechanics and Physics of Solids, vol. 47, no. 6, pp. 1239–1263, 1999. View at Publisher · View at Google Scholar · View at MathSciNet · View at Scopus
  46. C.-S. Han, H. Gao, Y. Huang, and W. D. Nix, “Mechanism-based strain gradient crystal plasticity—I. Theory,” Journal of the Mechanics and Physics of Solids, vol. 53, no. 5, pp. 1188–1203, 2005. View at Publisher · View at Google Scholar · View at MathSciNet · View at Scopus
  47. Y. Huang, S. Qu, K. C. Hwang, M. Li, and H. Gao, “A conventional theory of mechanism-based strain gradient plasticity,” International Journal of Plasticity, vol. 20, no. 4-5, pp. 753–782, 2004. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at Scopus
  48. Y. Huang, Z. Xue, H. Gao, W. D. Nix, and Z. C. Xia, “A study of microindentation hardness tests by mechanism-based strain gradient plasticity,” Journal of Materials Research, vol. 15, no. 8, pp. 1786–1796, 2000. View at Publisher · View at Google Scholar · View at Scopus
  49. S. Nikolov, C.-S. Han, and D. Raabe, “On the origin of size effects in small-strain elasticity of solid polymers,” International Journal of Solids and Structures, vol. 44, no. 5, pp. 1582–1592, 2007. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at Scopus
  50. C.-S. Han and S. Nikolov, “Indentation size effects in polymers and related rotation gradients,” Journal of Materials Research, vol. 22, no. 6, pp. 1662–1672, 2007. View at Publisher · View at Google Scholar · View at Scopus
  51. S. Swaddiwudhipong, L. H. Poh, J. Hua, Z. S. Liu, and K. K. Tho, “Modeling nano-indentation tests of glassy polymers using finite elements with strain gradient plasticity,” Materials Science and Engineering A, vol. 404, no. 1-2, pp. 179–187, 2005. View at Publisher · View at Google Scholar · View at Scopus
  52. T.-Y. Zhang, W.-H. Xu, and M.-H. Zhao, “The role of plastic deformation of rough surfaces in the size-dependent hardness,” Acta Materialia, vol. 52, no. 1, pp. 57–68, 2004. View at Publisher · View at Google Scholar · View at Scopus
  53. W. C. Oliver and G. M. Pharr, “Improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments,” Journal of Materials Research, vol. 7, no. 6, pp. 1564–1583, 1992. View at Publisher · View at Google Scholar · View at Scopus
  54. ISO, “Metallic materials—instrumented indentation test for hardness and materials parameters: Part 1: test method,” Tech. Rep. 14577-1, International Organization for Standardization, 2002. View at Google Scholar
  55. A. C. Fischer-Cripps, Nanoindentation, Springer, New York, NY, USA, 3rd edition, 2011.
  56. R. Saha and W. D. Nix, “Effects of the substrate on the determination of thin film mechanical properties by nanoindentation,” Acta Materialia, vol. 50, no. 1, pp. 23–38, 2002. View at Publisher · View at Google Scholar · View at Scopus
  57. R. Rodríguez and I. Gutierrez, “Correlation between nanoindentation and tensile properties influence of the indentation size effect,” Materials Science and Engineering A, vol. 361, no. 1-2, pp. 377–384, 2003. View at Publisher · View at Google Scholar · View at Scopus
  58. J. A. Tjernlund, E. K. Gamstedt, and Z.-H. Xu, “Influence of molecular weight on strain-gradient yielding in polystyrene,” Polymer Engineering & Science, vol. 44, no. 10, pp. 1987–1997, 2004. View at Publisher · View at Google Scholar · View at Scopus
  59. C.-S. Han, S. H. R. Sanei, and F. Alisafaei, “On the origin of indentation size effect and depth dependent mechanical properties of elastic polymers,” Journal of Polymer Engineering, 2015. View at Publisher · View at Google Scholar
  60. J. K. Deuschle, G. Buerki, H. M. Deuschle, S. Enders, J. Michler, and E. Arzt, “In situ indentation testing of elastomers,” Acta Materialia, vol. 56, no. 16, pp. 4390–4401, 2008. View at Publisher · View at Google Scholar · View at Scopus
  61. A. Flores and F. J. Baltá Calleja, “Mechanical properties of poly(ethylene terephthalate) at the near surface from depth-sensing experiments,” Philosophical Magazine A, vol. 78, no. 6, pp. 1283–1297, 1998. View at Google Scholar · View at Scopus
  62. C. A. Tweedie, G. Constantinides, K. E. Lehman, D. J. Brill, G. S. Blackman, and K. J. Van Vliet, “Enhanced stiffness of amorphous polymer surfaces under confinement of localized contact loads,” Advanced Materials, vol. 19, no. 18, pp. 2540–2546, 2007. View at Publisher · View at Google Scholar · View at Scopus
  63. Y. Hu, L. Shen, H. Yang et al., “Nanoindentation studies on Nylon 11/clay nanocomposites,” Polymer Testing, vol. 25, no. 4, pp. 492–497, 2006. View at Publisher · View at Google Scholar · View at Scopus
  64. R. V. S. Tatiraju, C.-S. Han, and S. Nikolov, “Size dependent hardness of polyamide/imide,” The Open Mechanics Journal, vol. 2, no. 1, pp. 89–92, 2008. View at Publisher · View at Google Scholar · View at Scopus
  65. W. W. Gerberich, N. I. Tymiak, J. C. Grunlan, M. F. Horstemeyer, and M. I. Baskes, “Interpretations of indentation size effects,” ASME Journal of Applied Mechanics, vol. 69, no. 4, pp. 433–442, 2002. View at Publisher · View at Google Scholar · View at Scopus
  66. N. I. Tymiak, D. E. Kramer, D. F. Bahr, T. J. Wyrobek, and W. W. Gerberich, “Plastic strain and strain gradients at very small indentation depths,” Acta Materialia, vol. 49, no. 6, pp. 1021–1034, 2001. View at Publisher · View at Google Scholar · View at Scopus
  67. C.-S. Han, “Indentation size effect in polymers,” in Advances in Materials Science Research, M. C. Wythers, Ed., vol. 10, chapter 15, pp. 393–413, Nova Science, New York, NY, USA, 2011. View at Google Scholar
  68. C.-S. Han, “Influence of the molecular structure on indentation size effect in polymers,” Materials Science and Engineering A, vol. 527, no. 3, pp. 619–624, 2010. View at Publisher · View at Google Scholar · View at Scopus
  69. X. Li and B. Bhushan, “Continuous stiffness measurement and creep behavior of composite magnetic tapes,” Thin Solid Films, vol. 377-378, pp. 401–406, 2000. View at Publisher · View at Google Scholar · View at Scopus
  70. T. K. Chaki and J. C. M. Li, “Latent hardening in highdensity polyethylene,” Journal of Applied Physics, vol. 56, no. 9, pp. 2392–2395, 1984. View at Publisher · View at Google Scholar · View at Scopus
  71. L. Shen, I. Y. Phang, L. Chen, T. Liu, and K. Zeng, “Nanoindentation and morphological studies on nylon 66 nanocomposites. I. Effect of clay loading,” Polymer, vol. 45, no. 10, pp. 3341–3349, 2004. View at Publisher · View at Google Scholar · View at Scopus
  72. L. Shen, I. Y. Phang, T. Liu, and K. Zeng, “Nanoindentation and morphological studies on nylon 66/organoclay nanocomposites. II. Effect of strain rate,” Polymer, vol. 45, no. 24, pp. 8221–8229, 2004. View at Publisher · View at Google Scholar · View at Scopus
  73. T. Liu, I. Y. Phang, L. Shen, S. Y. Chow, and W.-D. Zhang, “Morphology and mechanical properties of multiwalled carbon nanotubes reinforced nylon-6 composites,” Macromolecules, vol. 37, no. 19, pp. 7214–7222, 2004. View at Publisher · View at Google Scholar · View at Scopus
  74. L. Shen, I. Y. Phang, and T. Liu, “Nanoindentation studies on polymorphism of nylon 6,” Polymer Testing, vol. 25, no. 2, pp. 249–253, 2006. View at Publisher · View at Google Scholar · View at Scopus
  75. W. D. Zhang, L. Shen, I. Y. Phang, and T. Liu, “Carbon nanotubes reinforced nylon-6 composite prepared by simple melt-compounding,” Macromolecules, vol. 37, no. 2, pp. 256–259, 2004. View at Publisher · View at Google Scholar · View at Scopus
  76. G. Chandrashekar, F. Alisafaei, and C.-S. Han, “Length scale dependent deformation in natural rubber,” Journal of Applied Polymer Science, 2015. View at Publisher · View at Google Scholar
  77. J. K. Deuschle, H. M. Deuschle, S. Enders, and E. Arzt, “Contact area determination in indentation testing of elastomers,” Journal of Materials Research, vol. 24, no. 3, pp. 736–748, 2009. View at Publisher · View at Google Scholar · View at Scopus
  78. J. Deuschle, S. Enders, and E. Arzt, “Surface detection in nanoindentation of soft polymers,” Journal of Materials Research, vol. 22, no. 11, pp. 3107–3119, 2007. View at Publisher · View at Google Scholar · View at Scopus
  79. J. K. Deuschle, E. J. de Souza, E. Arzt, and S. Enders, “Nanoindentation studies on cross linking and curing effects of PDMS,” International Journal of Materials Research, vol. 101, no. 8, pp. 1014–1023, 2010. View at Publisher · View at Google Scholar · View at Scopus
  80. K. L. Johnson, Contact Mechanics, Cambridge University Press, 1985.
  81. I. N. Sneddon, “The relation between load and penetration in the axisymmetric boussinesq problem for a punch of arbitrary profile,” International Journal of Engineering Science, vol. 3, no. 1, pp. 47–57, 1965. View at Publisher · View at Google Scholar · View at MathSciNet · View at Scopus
  82. L. E. Govaert, P. H. M. Timmermans, and W. A. M. Brekelmans, “The influence of intrinsic strain softening on strain localization in polycarbonate: modeling and experimental validation,” Journal of Engineering Materials and Technology, Transactions of the ASME, vol. 122, no. 2, pp. 177–185, 2000. View at Publisher · View at Google Scholar · View at Scopus
  83. F. Yang, A. C. M. Chong, D. C. C. Lam, and P. Tong, “Couple stress based strain gradient theory for elasticity,” International Journal of Solids and Structures, vol. 39, no. 10, pp. 2731–2743, 2002. View at Publisher · View at Google Scholar · View at Scopus
  84. G. Kaupp, Atomic Force Microscopy, Scanning Nearfield Optical Microscopy and Nanoscratching, Application to Rough and Natural Surfaces, Springer, 2006.
  85. N. Garg and C.-S. Han, “A penalty finite element approach for couple stress elasticity,” Computational Mechanics, vol. 52, no. 3, pp. 709–720, 2013. View at Publisher · View at Google Scholar · View at MathSciNet · View at Scopus
  86. N. Garg and C.-S. Han, “Axisymmetric couple stress elasticity and its finite element formulation with penalty terms,” Archive of Applied Mechanics, vol. 85, no. 5, pp. 587–600, 2015. View at Publisher · View at Google Scholar · View at Scopus
  87. N. Garg, F. Alisafaei, G. Chandrashekar, and C.-S. Han, “Fiber diameter dependent deformation in polymer composites—a numerical study,” Submitted.
  88. L. Shen, W. C. Tjiu, and T. Liu, “Nanoindentation and morphological studies on injection-molded nylon-6 nanocomposites,” Polymer, vol. 46, no. 25, pp. 11969–11977, 2005. View at Publisher · View at Google Scholar · View at Scopus
  89. D. M. Ebenstein, “Nano-JKR force curve method overcomes challenges of surface detection and adhesion for nanoindentation of a compliant polymer in air and water,” Journal of Materials Research, vol. 26, no. 8, pp. 1026–1035, 2011. View at Publisher · View at Google Scholar · View at Scopus
  90. F. Carrillo, S. Gupta, M. Balooch et al., “Nanoindentation of polydimethylsiloxane elastomers: effect of crosslinking, work of adhesion, and fluid environment on elastic modulus,” Journal of Materials Research, vol. 20, no. 10, pp. 2820–2830, 2005. View at Publisher · View at Google Scholar · View at Scopus
  91. Y. Cao, D. Yang, and W. Soboyejoy, “Nanoindentation method for determining the initial contact and adhesion characteristics of soft polydimethylsiloxane,” Journal of Materials Research, vol. 20, no. 8, pp. 2004–2011, 2005. View at Publisher · View at Google Scholar · View at Scopus
  92. D. M. Ebenstein and K. J. Wahl, “A comparison of JKR-based methods to analyze quasi-static and dynamic indentation force curves,” Journal of Colloid and Interface Science, vol. 298, no. 2, pp. 652–662, 2006. View at Publisher · View at Google Scholar · View at Scopus
  93. S. Gupta, F. Carrillo, C. Li, L. Pruitt, and C. Puttlitz, “Adhesive forces significantly affect elastic modulus determination of soft polymeric materials in nanoindentation,” Materials Letters, vol. 61, no. 2, pp. 448–451, 2007. View at Publisher · View at Google Scholar · View at Scopus
  94. J. D. Kaufman and C. M. Klapperich, “Surface detection errors cause overestimation of the modulus in nanoindentation on soft materials,” Journal of the Mechanical Behavior of Biomedical Materials, vol. 2, no. 4, pp. 312–317, 2009. View at Publisher · View at Google Scholar · View at Scopus