Thermal sensitive fluorescent hyperbranched polymer without fluorophores

A thermal-light dual response hyperbranched polymer, poly(ethylene imine)-grafted-cyclohexane carboxylic acid (PEI-CCA), was designed and synthesized by introducing hydrophobic cyclohexyl units to the terminals of hyperbranched poly(ethylene imine) (PEI). Proper amounts of hydrophobic cyclohexyl units endue PEI-CCA with a hydrophobic-hydrophilic balance which leads to the thermo-sensitive property. And the peripheral modifier of PEI provides the resultant hyperbranched polymer with strong fluorescence without any traditional fluorophores. Both temperature response and fluorescence response can be controlled by adjusting the ratio of cyclohexyl groups. The intensities of fluorescence changed with temperature, pH and concentration were investigated.