Polymersome/silica capsules by 'Click'-chemistry

Polyisobutylene/poly (ethylene oxide) diblock copolymers (PIBn-PEOm) with variable blocklengths (n = 40, 75; m = 31, 52) have been prepared by a combination of living polymerization cationic methods and azide/alkyne 'click' chemistry. Allyl-telechelic PIBs are transformed into the respective telechelic PIB-azides (PIB-N-3) by a quantitative procedure. Coupling of the PIB-N-3 to acetylene-telechelic PEO-polymers is then quantitatively achieved by a Cu-I-mediated cycloaddition reaction. The resulting diblock copolymers reveal lamellar structures in solution at concentrations up to 35 wt.-%, whereas polymersomes are formed at lower concentrations. The resulting polymersomes can be silicified under inclusion of nanoparticles to generate micrometer-sized, multifunctional capsules with a silica shell.