Design of Stimuli-Responsive Dynamic Covalent Delivery Systems for Volatile Compounds (Part 1): Controlled Hydrolysis of Micellar Amphiphilic Imines in Water.

Despite their intrinsic hydrolysable character, imine bonds can become remarkably stable in water when self-assembled in amphiphilic micellar structures. In this work, we systematically studied some of these structures and the influence of various parameters that can be used to take control of their hydrolysis, including pH, concentration, the position of the imine function in the amphiphilic structure, relative lengths of the linked hydrophilic and hydrophobic moieties. Thermodynamic and kinetic data led us to the rational design of stable imines in water, partly based on the location of the imine function within the hydrophobic part of the amphiphile and on a predictable quantitative term that we define as the total hydrophilic-lipophilic balance (HLB). In addition, we show that such stable systems are also stimuli-responsive and therefore, of potential interest in trapping and releasing micellar components on demand.