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RESEARCH PRODUCT
On the Use of the Nanoindentation Unloading Curve to Measure the Young's Modulus of Polymers on a Nanometer Scale
Stefano PiccaroloDavide Tranchidasubject
chemistry.chemical_classificationMaterials sciencenanoindentationPolymers and Plasticsbusiness.industrypolymerOrganic ChemistryYoung's modulusPolymerNanoindentationAmorphous solidsymbols.namesakeContact mechanicsOpticschemistryelastic moduluIndentationMaterials Chemistrysymbolsmechanical propertieatomic force microscopy (AFM)NanometreComposite materialbusinessElastic modulusdescription
Summary: The nanoindentation test is a fundamental tool to assess the link between morphology and mechanical properties. The preliminary results of a more exhaustive study about the applicability to polymers of the most used procedure to determine elastic modulus by indentation are reported in this short communication. A departure of the experimental conditions from the theoretical assumptions and results that give rise to the Oliver and Pharr analysis is shown to occur under a wide range of experimental conditions, with applied loads and penetration depths covering several orders of magnitude and using different indenter geometries. Unloading curves with exponents significantly larger than 2 are observed in disagreement with the contact mechanics approach used by Oliver and Pharr. An AFM image obtained in non contact mode of an indentation induced by a sharp AFM tip with a maximum applied load of ca 1.2 µN on amorphous PET.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2005-11-14 | Macromolecular Rapid Communications |