Introducing kosmotropic salts enhances protein stability
and reduces
solubility by withdrawing water from the protein surface, leading
to ‘salting out’, a phenomenon we have mimicked in supramolecular
polymers (SPs). Under the guidance of Ag+, folic acid (FA)
self-assembled in water through slipped-stacking and hydrophobic interactions
into elongated, robust one-dimensional SPs, resulting in thermo-stable
supergels. The SPs exhibited temperature and dilution tolerance, attributed
to the stability of the FA-Ag+ complex and its hydrophobic
stacking. Importantly, FA-Ag+ SP’s stability has
been augmented by the kosmotropic anions, such as SO4
2–, strengthening hydrophobic interactions in the SP,
evident from the enhanced J-band, causing improvement of gel’s
mechanical property. Interestingly, higher kosmotrope concentrations
caused a significant decrease in SP’s solubility, leading to
precipitation of the reinforced SPsa ‘salting out’
effect. Conversely, chaotropes like ClO4
– slightly destabilized hydrophobic stacking and promoted an extended
conformation of individual SP chain with enhanced solubility, resembling
a ‘salting in’ effect.