Scaling of Flory-Huggins interaction parameter for polyols with chain length and number of hydroxyl groups

The Flory-Huggins-Free-Volume (FHFV) theory, describing the moisture sorption of carbohydrates, is extended towards a wider range of compounds. Earlier application of the FHFV theory has been to carbohydrate/water mixtures, as can be found in foods. Now, we have extended the theory towards polyols (or polyalcohols) which are investigated in as proxies for secondary organic aerosols, whose behaviour is important for understanding climate behaviour. The investigated polyols are characterized by the ratio of the number hydroxyl groups NOH and the number of carbon atoms NC , which is often lower than ratios found in carbohydrates in food materials. We have found that the value of the Flory-Huggins interaction parameter is a function of the solute molecular properties, namely its chain length NC and the ratio NOH/NC of the solute. The deviation of this ratio from 12 can be viewed as a measure for its hydrophilicity. For food science, the extension of the theory has also significant implications, as the interaction parameter of newly investigated ingredients (rich in hydroxyl groups) can be estimated by means of the molecular properties. One must think of insoluble food fibers like xylan-glucans or arabinoxylans, or modified biopolymers based on starch or cellulose. Flory-Huggins interaction parameter of carbohydrates depend on chain length and hydrophilicity. [Display omitted] •Flory-Huggins interaction parameter can be linked to chain length and relative hydrophilicity.•Relative hydrophilicity is related to ratio of hydroxyl groups to number of carbon atoms.•Theory is tested on different polyols, and translated to polysaccharides as xylo-glucans.