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On the indentation recovery and fleeting hardness of polymers

Published online by Cambridge University Press:  03 March 2011

Catherine A. Tweedie
Affiliation:
Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
Krystyn J. Van Vliet*
Affiliation:
Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
*
a) Address all correspondence to this author. e-mail: [email protected]
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Abstract

Accurate mechanical characterization of viscoelastoplastic materials in small volumes is required for the development of polymeric thin film, nanocomposite, and biomedical applications. Instrumented indentation-based approaches are increasingly implemented to quantify the resistance to permanent deformation of such systems via time-independent analyses. Here, we quantify the significant post-indentation recovery of several bulk polymers via time-lapsed scanning-probe microscopy under ambient conditions, indicating up to 80% recovery of both indentation depth and volume within 48 h. This viscoelastic response demonstrates that indentation hardness values for these polymers are accurate within 10% for less than 5 min to 3.5 days post-indentation, neglecting any other analytical or experimental errors. Further, although the extent and rates of volumetric recovery depend strongly on loading history and polymer structure/physical properties, deformation resistance inferred from indentation hardness does not quantitatively or qualitatively predict recoverable work or residual deformation of polymer surfaces.

Type
Articles
Copyright
Copyright © Materials Research Society 2006

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References

REFERENCES

1.VanLandingham, M.R., Villarrubia, J.S., Guthrie, W.F., Meyers, G.F.: Nanoindentation of polymers: An overview. Macromol. Symp. 167, 15 (2001).3.0.CO;2-T>CrossRefGoogle Scholar
2.Briscoe, B.J., Sebastian, K.S.The elastoplastic response of poly(methyl methacrylate) to indentation. Proc. R. Soc. London Ser. A 452, 439457 (1996).Google Scholar
3.Briscoe, B.J., Evans, P.D., Biswas, S.K., Sinha, S.K.: The hardnesses of poly(methylmethacrylate). Tribology International 29, 93 (1996).CrossRefGoogle Scholar
4.Klapperich, C., Komvopoulos, K., Pruitt, L.: Nanomechanical properties of polymers determined from nanoindentation experiments. J. Tribol-T Asme. 123, 624 (2001).CrossRefGoogle Scholar
5.Oliver, W.C., Pharr, G.M.: An improved technique for determining hardness and elastic-modulus using load and displacement sensing indentation experiments. J. Mater. Res. 7, 1564 (1992).CrossRefGoogle Scholar
6.Chang, B.T.A., Li, J.C.M.: Indentation recovery of amorphous materials. Scripta Metall Mater. 13, 51 (1979).CrossRefGoogle Scholar
7.Low, I.M.: Effects of load and time on the hardness of a viscoelastic polymer. Mater. Res. Bull. 33, 1753 (1998).CrossRefGoogle Scholar
8.Lorenzo, V., Perena, J.M., Fatou, J.G., Mendezmorales, J.A., Aznarez, J.A.: Delayed elastic recovery of hardness indentations in polyethylene. J. Mater. Sci. 23, 3168 (1988).CrossRefGoogle Scholar
9.Lorenzo, V., Perena, J.M., Fatou, J.M.G., Mendezmorales, J.A., Aznarez, J.A.: Interference microscopy measurements of depth at Vickers hardness indentations in polyethylene. J. Mater. Sci. Lett. 6, 756 (1987).CrossRefGoogle Scholar
10.Chang, B.T.A., Li, J.C.M.: Indentation recovery of atactic polystyrene. J. Mater. Sci. 15, 1364 (1980).CrossRefGoogle Scholar
11.Kung, T.M., Li, J.C.M.: Recovery processes in amorphous polymers. J. Mater. Sci. 22, 3620 (1987).CrossRefGoogle Scholar
12.Yang, F.Q., Zhang, S.L., Li, J.C.M.: Impression recovery of amorphous polymers. J. Electron. Mater. 26, 859 (1997).CrossRefGoogle Scholar
13.Tweedie, C.A., Smith, J.F., Van Vliet, K.J.: Nanomechanics of Polymer Energy Absorption, (Materials Research Society, Boston, MA, 2004).Google Scholar
14.Young, R.J., Lovell, P.A.: Introduction to Polymers (Chapman & Hall, New York, 1991).CrossRefGoogle Scholar
15.Brulet, A., Boue, F., Cotton, J.P.: About the experimental determination of the persistence length of wormlike chains of polystyrene. J. Phys. II 6, 885 (1996).Google Scholar
16.Bicerano, J.: Chain stiffness of liquid crystalline polyesters. 1. Characteristic ratio and persistence length. Comput. Theor. Polym. Sci. 8, 9 (1998).CrossRefGoogle Scholar
17.Nikolov, S., Doghri, I.: A micro/macro constitutive model for the small-deformation behavior of polyethylene. Polymer 41, 1883 (2000).CrossRefGoogle Scholar
18.Liu, Y.G., Bo, S.Q., Zhu, Y.J., Zhang, W.H.: Studies on the intermolecular structural heterogeneity of a propylene-ethylene random copolymer using preparative temperature rising elution fractionation. J. Appl. Polym. Sci. 97, 232 (2005).CrossRefGoogle Scholar
19.Dinelli, F., Leggett, G.J., Shipway, P.H.: Nanowear of polystyrene surfaces: Molecular entanglement and bundle formation. Nanotechnology 16, 675 (2005).CrossRefGoogle Scholar
20.Soles, C.L., Douglas, J.F., Wu, W.L., Dimeo, R.M.: Incoherent neutron scattering as a probe of the dynamics in molecularly thin polymer films. Macromolecules 36, 373 (2003).CrossRefGoogle Scholar
21.Nielson, L.E.: Mechanical Properties of Polymers and Composites, (Marcel Dekker, New York, 1974).Google Scholar
22.Cheng, Y.T., Cheng, C.M.: Scaling, dimensional analysis, and indentation measurements. Mater. Sci. Eng., R 44, 91 (2004).CrossRefGoogle Scholar
23.Dao, M., Chollacoop, N., Van Vliet, K.J., Venkatesh, T.A., Suresh, S.: Computational modeling of the forward and reverse problems in instrumented sharp indentation. Acta Mater. 49, 3899 (2001).CrossRefGoogle Scholar
24.Wang, L.G., Ganor, M., Rokhlin, S.I., Grill, A.: Nanoindentation analysis of mechanical properties of low to ultralow-dielectric constant SiCOH films. J. Mater. Res. 20, 2080 (2005).CrossRefGoogle Scholar