Conetworks and Organogels of Poly(methyl acrylate) Crosslinked with Degradable, Disulfide and β-Thioester Containing Bisacrylate Macromonomer

Here, we report, for the first time, on a new class of sulfur-containing double hydrophopbic conetworks, poly(methyl acrylate)-l-poly(3,6-dioxa-1,8-octane-dithiol-co-poly(ethylene glycol) diacrylate) (PMA-l-P(DODT-co-PEGDA). Direct one-pot synthesis of acrylate-telechelic P(DODT-co-PEGDA) macromonomer in a gram-scale for the preparation of the conetworks was obtained by copolymerization of DODT with PEGDA via simultaneous oxidative disulfide formation and thiol–ene Michael addition click reactions. Conetworks with a broad composition range of 20–70 wt% sulfur-rich P(DODT-co-PEGDA) macrocrosslinker contents were obtained by radical copolymerization. High gel fractions and composition near to that of the feed ratios verified successful conetwork synthesis. DSC analysis indicates forced blending of the immiscible PMA and P(DODT-co-PEGDA) in the conetworks by one single Tg, which deviates from both the additive rule and the Fox equation for miscible blends. These novel conetworks exhibit high thermal stability up to ~300 °C and independent decomposition patterns of the components in two separate steps. The PMA-l-P(DODT-co-PEGDA) conetworks behave as organogels by swelling in organic solvents, such as THF, acetone, toluene, with composition dependent swelling degrees up to ~900%. Degradation by breaking the disulfide bonds with thiols followed by hydrolysis with NaOH led to complete disintegration of the PMA-l-P(DODT-co-PEGDA) conetworks. These findings enable establishing a new platform for the rational design of a variety of novel sulfur-containing functional and degradable macromolecular assemblies.