INQUIMAE   12526
INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
artículos
Título:
A model for the dependence of the electrical conductance with the applied stress in insulating-conducting composites
Autor/es:
R. MARTÍN NEGRI, S. RODRÍGUEZ, DELIA BERNIK, FERNANDO MOLINA, ANA PILOSOF, OSCAR PEREZ
Revista:
JOURNAL OF APPLIED PHYSICS
Editorial:
AMER INST PHYSICS
Referencias:
Año: 2010 vol. 107 p. 113703 - 113717
ISSN:
0021-8979
Resumen:
A model for the dependence of the electrical conductance, G, with the strain induced by external
mechanical stress in conducting particles-polymer composites is presented. The model assumes that
the percolation probability between neighboring particles must depart from a scale-invariant
behavior but saturate at moderated-high strains, reaching percolation paths saturation, with sigmoid
dependence. This dependence is obtained by proposing a dynamic picture where contacts or bonds
between neighboring particles are created but also destructed when a stress is applied and relatively
moderated or high strains, , are produced in the composite. The electrical conductance of prepared
graphite-polydimethylsiloxane composites were measured as function of the applied pressure and
fitted by the presented model. The elastic response to the uniaxial compression was studied using a
texture analyzer. The possibility of nonuniversal effects in the conduction critical exponent, t, was
taken into account. It is concluded that the saturation of the response in the G versus plots cannot
be assigned to nonuniversal behavior of the exponent t, or to saturation of the elastic response. On
the other hand, the presented model accounts for all the main experimental features observed in
these systems and for previously reported data of elastomer composites. The simulated behavior of
the piezoresistivity coefficient is also in qualitative agreement with previous reports. © 2010
American Institute of Physics. doi:10.1063/1.3410799