Characterization of the behavior of hydrophobic domain in hydrogel on hydrophobic and hydrophilic interfaces

Biocompatible hydrogels are of central importance for many applications in the field of life science. A central point in all such applications is their adhesion to a solid surface, which is typically achieved by the application of soft pressure. We have developed such a hydrogel that contains cholic acid groups and whose adhesion underwater becomes stronger with increased content of cholic acid. Assumed is here the formation of hydrophobic domains of the cholic acid moieties at the interface that should also depend on the extent of hydrophobicity of the substrate. Neutron reflectometry in D2O shall be done in order to see how the hydrogel structure at the interface changes as a function of applied pressure and the content of cholic acid in the hydrogel. This is essential to understand macroscopic adhesion in terms of mesoscopic structure and thereby rationalize molecular hydrogel design.