Synthesis Of Thermoresponsive AIE Supramolecular Complexes And Study On Phase Transition In Dilute Solution

In this paper,a method for sensitively probing the phase transitions of thermoresponsive aggregation induced emission(AIE)supramolecular systems in dilute solutions was developed by using fluorescence technique.On the basis of hydrogen bonding interaction,electrostatic attraction,and hydrophobic-hydrophobic interactions between amino-containing thermoresponsive hyperbranched polymers(HPEI-IBAm)and carboxylic acid–containing AIE molecules(TPE~COOH),the thermoresponsive AIE supramolecular complexes were prepared.The supramolecular complexes were then characterized by ~1H NMR,2D ~1H NOESY spectroscopy,transmission electron microscopy(TEM)and dynamic light scattering(DLS).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 phase transition temperature(PTT),whereas the other signal showed a monotonous emission decrease with increasing temperature accompanied with a slope increase change around PTT.From these two different temperature-dependent emission responses,PTTs of these thermoresponsive AIE supramolecular complexes could be facilely read off even in dilute solution,where the traditional turbidimetry technique lose efficacy.At the same time,the phase transition behavior of the as-prepared supramolecular complexes was studied in detail by using fluorescence technique from the following factors:solvent composition,complex concentration,complex composition,inorganic anions and inorganic cations.