Microorganism metabolic activity can facilitate the formation of cellular material systems that have unusual mechanical and physical properties. In the living world microorganisms are commonly used for preparing porous food by fermentation; here carbon nanotubes, graphene nanoplatelets, and a mix of them are dispersed in liquid silicone rubber with single-cell fungi of commercial beer yeast. The fermentation of such microorganisms during the gelling of the silicone matrix results in bionic composites with buckled/col- lapsed cells that infer, as rationalized with an analytical model and excluded in a abiotic experimental comparison, auxetic properties. During stretching it is found that the Poisson’s ratio of such composites changes sign, from negative to positive, and the variation of the electrical resistance is negative. In addition to the conductivity increment, a general increment of the stretch- ability and damage resistance with respect to the composites prepared by abiotic process is observed. Bionic composites, even if in their infancy, can thus be multifunctional and superior to their traditional/abiotic counterparts.
Microorganism metabolic activity can facilitate the formation of cellular material systems that have unusual mechanical and physical properties. In the living world microorganisms are commonly used for preparing porous food by fermentation; here carbon nanotubes, graphene nanoplatelets, and a mix of them are dispersed in liquid silicone rubber with single-cell fungi of commercial beer yeast. The fermentation of such microorganisms during the gelling of the silicone matrix results in bionic composites with buckled/collapsed cells that infer, as rationalized with an analytical model and excluded in a abiotic experimental comparison, auxetic properties. During stretching it is found that the Poisson's ratio of such composites changes sign, from negative to positive, and the variation of the electrical resistance is negative. In addition to the conductivity increment, a general increment of the stretchability and damage resistance with respect to the composites prepared by abiotic process is observed. Bionic composites, even if in their infancy, can thus be multifunctional and superior to their traditional/abiotic counterparts.
Graphene and Carbon Nanotube Auxetic Rubber Bionic Composites with Negative Variation of the Electrical Resistance and Comparison with Their Nonbionic Counterparts
VALENTINI, LUCA
Writing – Original Draft Preparation
;
2017
Abstract
Microorganism metabolic activity can facilitate the formation of cellular material systems that have unusual mechanical and physical properties. In the living world microorganisms are commonly used for preparing porous food by fermentation; here carbon nanotubes, graphene nanoplatelets, and a mix of them are dispersed in liquid silicone rubber with single-cell fungi of commercial beer yeast. The fermentation of such microorganisms during the gelling of the silicone matrix results in bionic composites with buckled/collapsed cells that infer, as rationalized with an analytical model and excluded in a abiotic experimental comparison, auxetic properties. During stretching it is found that the Poisson's ratio of such composites changes sign, from negative to positive, and the variation of the electrical resistance is negative. In addition to the conductivity increment, a general increment of the stretchability and damage resistance with respect to the composites prepared by abiotic process is observed. Bionic composites, even if in their infancy, can thus be multifunctional and superior to their traditional/abiotic counterparts.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
