By measuring diffusion behavior of PEG with various molecular mass in SA/CS-CaCl2/PMCG microcapsules
it was shown that molecular mass cut-off of the microcapsules membrane was about 2000. Meanwhile
diffusion of small solutes including glucose
lactose
ethanol and L-glutamic acid in three kinds of SA/CS-CaCl2/PMCG microcapsules were determined. The mixed diffusion coefficients Dm and diffusion coefficients in capsular membrane D1 were calculated by a diffusion model. The results showed that the mixed diffusion coefficients Dm increased at first and subsequently slightly decreased with increasing concentration of PMCG
whereas D1 increased continuously. D1《Dm indicated that the main resistance in mass transfer was mainly on the capsular membrane.