Thermoresponsive AIE supramolecular complexes in dilute solution: sensitively probing the phase transition from two different temperature-dependent emission responses

Abstract

Sensitively probing the phase transition of an AIE thermoresponsive supramolecular system in dilute solution was developed by using a fluorescence technique in this study. Thermoresponsive AIE supramolecular complexes were prepared on the basis of electrostatic attraction, hydrogen bonding interactions and host–guest interactions between amino-containing thermoresponsive hyperbranched polymers and carboxylic acid-containing AIE molecules. Different from the other thermoresponsive AIE systems, the as-prepared thermoresponsive AIE supramolecular complexes exhibited two different temperature-dependent emission responses, i.e. one signal experienced an obvious emission boost with increasing temperature around the phase transition temperature (PTT), whereas the other signal showed a monotonous emission decrease with increasing temperature accompanied with a slope increase change around the PTT. From these two different temperature-dependent emission responses, the PTTs of these thermoresponsive AIE supramolecular complexes could be facilely read-off even in dilute solution, where the traditional turbidimetry technique loses efficacy. The influence of solvent composition, complex concentration, complex composition, inorganic anions and inorganic cations on the phase transition behavior of the as-prepared supramolecular complex was explored in detail by using the fluorescence technique.