Structurally dependent self-assembly and luminescence of polyoxometalate-cored supramolecular star polymers

Abstract

A series of hybrid supramolecular star polymers (SSPs) consisting of a polyoxometalate EuW₁₀O₃₆⁹⁻ (EuW₁₀) core and different length of polystyrene arms have been fabricated by a “core-first” method, in which the anionic EuW₁₀ clusters were firstly encapsulated by cationic molecules with trithioester terminal groups and subsequently polystyrene arms were grafted by reversible addition–fragmentation chain-transfer (RAFT) polymerization. The SSPs exhibit structurally dependent self-assembly behaviours in solution, at the air–water interface and solid state. It was found that the SSPs with short arms form large assemblies with a diameter over 100 nm in chloroform, while those with long arms tend to be mono-dispersed. Meanwhile, the distance between the EuW₁₀ cores of adjacent SSPs in Langmuir monolayers and casting films can be precisely adjusted by PS arms, which leads to a tunable colour purity of EuW₁₀ luminescence. This tight structure–property relationship enables the polyoxometalate-cored SSPs to act as potential building blocks for the construction of hybrid polymer materials with controllable functions.