Synthesis And Characterization Of The Hyperbranched Polymer Functionalized Carbon Dots With Multistimuli-responsive Properties

In this article, The pyrolysis of hyperbranched polyethylenimine (PEI) andglycerol mixture under microwaves generated the carbon dot (CD) functionalizedwith PEI (CD-PEI). Isobutyric amide (IBAm) groups were attached to CD-PEIthrough the amidation reaction of isobutyric anhydride and PEI moiety, whichresulted in the thermoresponsive CD-PEI-IBAms.CD-PEI-IBAms were not only thermoresponsive, but also responded to otherstimuli, including inorganic salt, pH and loaded organic guests. The cloud pointtemperature (Tcp) of the aqueous solutions of CD-PEI-IBAms could be modulated ina broad range through changing the number of IBAm units of CD-PEI-IBAm orvarying the type and concentration of the inorganic salts, pH and loaded organicguests. Low pH, the traditional salting-in anion and polar organic guests increased theTcppronouncedly, whereas high pH, the traditional salting-out anions and apolarorganic guest favored the decrease of Tcp.All the obtained CD-PEI-IBAms were photo-luminescent, which could beinfluenced a little or negligibly by the added salts, pH and the organic guestsencapsulated.