Synthesis of a Block Copolymer Containing and Self-Immolative Block

Block copolymers (BCPs) can self-assemble into periodic nanostructures, which make them attractive for a multitude of applications. For lithographic patterning, the ability to selectively remove one block is particularly beneficial. This process often requires harsh conditions and usually damages the other block, diminishing the fidelity of subsequent pattern transfer steps. To solve this problem, a BCP was synthesized which contained a polymer that undergoes rapid depolymerization when exposed to strong acids. Poly(dihydroxy-tetrahydro naphthalene) (poly(DHTN)) was synthesized under high mechanical stirring from DHTN and dibromomethane in a two-phase reaction mixture. The poly(DHTN) homopolymer was coupled to azide-terminated poly(trimethylsilyl styrene) by the copper-catalyzed azide-alkyne click reaction to form the block copolymer. Selective depolymerization of the poly(DHTN) block was demonstrated in solution when mixed with a strong acid catalyst.