Experimental investigation of the subdiffusion in a membrane system

We present experimental results on the anomalous diffusion in a membrane system which are obtained by means of the laser interferometric technique. When the polyethylene glycol 2000 (PEG2000) diffuses across the membrane into the agarose gel solution, the thickness of the so-called near-membrane layer δ, which is defined as a distance where the substance concentration drops k times, evolves with time t as tγ with γ<0.5, manifesting a subdiffusive character of the process. The concentration profiles C(x,t) scale as tβF(x/tγ), where the exponents β and γ are fixed.