The physicochemical behavior in aqueous solution of propylene glycol alginate and of its hydrophobically-modified derivatives is governed, especially in the dilute regime, by the occurrence or the absence of both long range electrostatic repulsions and hydrophobic attractions. According to the salt concentration in the aqueous polymer solution under concern, the resulting conformations may be fully expanded or, on the contrary, shrunken and tight. Such a difference results in some discrepancies in the viscometric data, depending on whether the measurements are performed by a high shear capillary technique or with a low shear rotatory instrument. Further indications of the behavior of these derivatives in dilute aqueous solution are drawn from fluorescence and surface tension correlations.