Mechanical studies of sol-gel transition: Universal behavior of elastic modulus

The critical behavior of the shear modulus of agarose gel was studied as a function of concentration and temperature. Experimental evidence is presented that the elasticity exponent agrees with the conductivity exponent of a percolating resistor network. It is found that the value of the elasticity exponent of agarose gel is independent of the path to the phase boundary. These results strongly suggest that the elastic behavior of gel in the critical region can be explained by the scalar elasticity model of percolation theory irrespective of the mechanism of gelation.