Aqueous microgels modified by wedge-shaped amphiphilic molecules via acid–base interaction: Effect of alkyl chain length

We report on the synthesis and properties of aqueous poly(N-vinylcaprolactam-co-acetoacetylethylmethacrylate-co-vinylimidazole) microgels with controlled degree of hydrophobic modification. Water-insoluble wedge-shaped sulfonic acid molecules with alkyl chains of different lengths were integrated into microgels via acid–base interaction. Hydrophobized microgels retain their colloidal stability in water. The length of the alkyl chain in the wedge-shaped molecules has a significant influence on their size, loading capacity and environmental sensitivity (thermochromic effect of the dye-loaded microgels). Furthermore, the incorporation into the hydrophobized microgels of dexamethasone, an important anti-inflammatory corticoid medicine, as well as its in vitro release profiles was investigated.