Core–Shell Double Gyroid Structure Formed by Linear ABC Terpolymer Thin Films

The synthesis and self‐assembly in thin‐film configuration of linear ABC triblock terpolymer chains consisting of polystyrene (PS), poly(2‐vinylpyridine) (P2VP), and polyisoprene (PI) are described. For that purpose, a hydroxyl‐terminated PS‐b‐P2VP (45 kg mol−1) building block and a carboxyl‐terminated PI (9 kg mol−1) are first separately prepared by anionic polymerization, and then are coupled via a Steglich esterification reaction. This quantitative and metal‐free catalyst synthesis route reveals to be very interesting since functionalization and purification steps are straightforward, and well‐defined terpolymers are produced. A solvent vapor annealing (SVA) process is used to promote the self‐assembly of frustrated PS‐b‐P2VP‐b‐PI chains into a thin‐film core–shell double gyroid (Q230, space group: Ia3¯d) structure. As terraces are formed within PS‐b‐P2VP‐b‐PI thin films during the SVA process under a CHCl3 vapor, different plane orientations of the Q230 structure ((211), (110), (111), and (100)) are observed at the polymer–air interface depending on the film thickness. Frustrated PS‐b‐P2VP‐b‐PI chains, produced by coupling a PS‐b‐P2VP‐OH with a carboxyl‐terminated polyisoprene via a Steglich esterification reaction, are self‐assembled into a thin‐film core–shell double gyroid structure. This Q230 structure exhibits different plane orientations depending on the film thickness.