The bridging of the electrodes by the induced columnar structure of urethane-modified polypropylene glycol (UPPG) is a dominant feature of the response of electro-rheological UPPG/dimethylsiloxane polymeric blends to the imposed electric field. The breaking up and formation of the bridging columns in flow is described as a stochastic process affecting the macroscopic flow behaviour of blends modelled by the Maxwell-like rheological equation. The results show that the proposed theological equation describes well the theological characteristics measured at steady and transient shear-flows.