Abstract: The present disclosure relates to a process for making a branched copolymer comprising reacting polymer monomers with macro-azo polyethylene glycol (PEG) initiators and cross-linkers, in the presence of a chain transfer agent, wherein said process comprises the step of traditional radical polymerization. The process further comprises a step of dialysis to obtain polymer nano-particles. The process further comprises the step of loading the polymer nanoparticles with a hydrophobic compound. The present disclosure also relates to the use of the polymer nanoparticles for the slow release of a hydrophobic compound in a neutral or alkaline environment or the fast release of a hydrophobic compound in an acidic environment.