Research On Pressure/Temperature Characteristics Of Conductive Rubber For Flexible Tactile

With the advancement of technology and the increasing demand of industry, flexible sensors have been applied in many fields. Conductive rubber filled by carbon black is an excellent conductive composite material for the fabrication of flexible sensor. In this article, the conductive properties and conductive mechanism of carbon black filled conductive rubber were discussed, and the piezoresistive effect and temperature effect were analyzed.This article focused on the conductive pathway theory and electron tunneling effect, and the two piezoresistive models were developed respectively based on the conductive mechanism theory of conductive rubber.A series of experiments were designed to unravel the factors affecting the conductivity and piezoresistive characteristics of carbon black filled conductive rubber. The conductivity and piezoresistivity of conductive rubber filled with different sorts of carbon black were measured and the results showed that in a certain range, with the decrease of particle size and the increase of specific surface area of carbon black, the conductivity and piezoresistivity of conductive rubber enhanced, while to a certain limit, the decrease of particle size and the increase of specific surface area has little effect on the conductivity and piezoresistivity. The conductivity and piezoresistive characteristics of conductive rubber showed different characteristics in both carbon black and only a carbon black. The conductive rubber material internal microstructure was analyzed by scanning electron microscope, the result showed that the conductivity of conductive rubber is affected on the state of dispersion of the carbon black particles in the conductive rubber.The temperature characteristic of conductive rubber was researched through the experiment, the conductive rubber was filled alone carbon black and both carbon black. Experimental results illustrate that the conductive rubber shows PTC and NTC with temperature rising when conductive rubber alone filled acetylene black. The conductive rubber showed that NTC is due to the thermal disturbance dominate and PTC is the thermal expansion dominate. Conductive rubber filled acetylene black and N472showed positive temperature effect with temperature rising, due to thermal expansion and thermal disturbance exist at the same time, the thermal expansion plays a leading role, so that the conductive rubber showed positive temperature effect. At last, improving the sensitivity of sensor temperature senders method, reducing the error. Finally the temperature compensation method is proposed to improve the sensitivity of the sensor and reduce the error.The mechanism of nano-modified material with conductive rubber was researched. Due to the special nature of nano modified material, when mixed with the polymer nanoparticles showed different from other material characteristics. The resistivity of the conductive rubber presented irregular change with nano-modified materials Al2O3, the small amount of nano-modified materials Al2O3not make conductive rubber internal agglomerates of carbon black particles dispersed, so that the resistivity doesn’t change significantly, increase the amount of nano-modified materials Al2O3, reduce the concentration of carbon black particles in the mixture and the resistivity decreases, but the appropriate adding nano-modified materials Al2O3can improve the stability of the conductive rubber, but appropriate adding nano-modified materials Al2O3can improve the stability of the conductive rubber. The temperature characteristic of the conductive rubber presented irregular change adding nano-modified materials Al2O3with increasing temperature.