*2.3. Synthesis of Graft Copolymers PI-g-(PHEMA-g-PCL)*

The synthesis of the copolymer was carried out by ROP of CL in bulk on PI-*g*-PHEMA. A typical synthesis procedure is as follows: 0.05 g (0.23 mmol per initiating group) of PI-*g*-PHEMA was added to a 25-mL Schlenk flask equipped with a magnetic stirrer, and three freeze−pump−thaw cycles were carried out (evacuation for 15 min), after which the flask was filled with argon. Then, 1.2 mL (0.011 mol) of ε-caprolactone was introduced in an argon flow and thermostated at 130 ◦C using an oil bath. After complete dissolution of the macroinitiator, 0.05 mL (0.15 mmol) of Sn(Oct)2 was introduced into the reaction in an argon flow. Upon completion of polymerization, the reaction mixture was cooled to room temperature and diluted with methylene chloride. The resulting solution was passed through a silica gel column to purify the product from catalyst and monomer impurities. The solution was then concentrated on a rotary evaporator and the product was precipitated into cooled petroleum ether. The polymer was dried under vacuum at 30 ◦C.

#### *2.4. Introduction of Azide Groups into Polyimide*

The functionalization of the polyimide with azide groups was carried out as follows. A weighed portion of PI2 macroinitiator (0.5 g, 0.66 mmol per initiating group) (Figure 1) and DMF (14.4 mL, 0.19 mol) was placed in a 25-mL round-bottom flask equipped with a magnetic stirrer, and the mixture was stirred until the powder was completely dissolved. Then NaN3 (0.214 g, 3.3 mmol) was added to the flask and purged with argon for 30 min. The mixture was stirred on a magnetic stirrer at room temperature overnight. The reacted polymer was precipitated into methanol. The filtered powder was dried under vacuum at 50 ◦C.
