Tuning the Hydrophobicity of Agar Hydrogel with Substituent Effect

Natural polymer agar-forming hydrogel exhibits such a high hydrophilic character for absorbing large quantities of water in a 3D cross-linked network structure. This study presents an advanced integrative strategy to control the hydrophobicity of the agar hydrogel. We synthesized the hydrophobically modified agarose (HMA, Agarose-g-C18) substituted with octadecyl chains, consisting of the optimized degree of substitution (DS). Then, in situ hydrogel forming of agars with HMAs, varying mixing ratios, generated the agar hydrogels that possess various hydrophilic/hydrophobic balances. We analyzed the physical and structural properties via DSC, SEM, UTM, and contact angle for substitution effects. Overall, this new strategy to prepare the agar hydrogel with hydrophilic/hydrophobic balances would greatly serve to facilitate a wide array of the agars used in microorganism culturing, electrophoresis, tissue engineering, cosmetic research, etc.