Capillary effects of submicron heterogeneities in aqueous solutions of sugars. The additional mechanism of microfluidics

•Submicron heterogeneities spontaneously form in aqueous solutions of sugars.•Submicron heterogeneities are destroyed in glass capillaries.•This factor may be an important mechanism of microfluidics. In this paper, we study submicron heterogeneities (SMH) that spontaneously form in aqueous solutions of sugars: glucose, fructose and sucrose, with a concentration of 0.5 mol%. These solutions were passed through glass capillaries with a diameter of about 6 and 13 µm, which led to a decrease in the concentration of SMH without significantly changing their size. For capillaries of smaller diameter, this effect is more pronounced. The decrease in the concentration of SMH is not associated with their mechanical destruction or adsorption on the surface of capillaries. This phenomenon is explained by the destruction of SMH as a result of their interaction with the hydrophilic surface of the capillary. The fundamental differences between the presence of SMH in microfluidic conditions and bulk reservoirs are discussed. This phenomenon should be taken into account in microfluidics.