Thermo-Responsive Microgels Based in Encapsulated Carbon Quantum Dots
In this work carbon quantum dots (CQDs) nanoparticles are synthesized from D-lactose using a hydrothermal method and then they are coated with polyethyleneglycol (CQDs@PEG).These particles exhibit a monodisperse spherical morphology with an average particle size of ~4 nm. Nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR) showed the presence of the hydroxyl groups from the ethylene glycol molecules grafted on the CQDs surface, which confirms that PEG was covalently attached to the nanoparticles surface. Fluorescence analysis demonstrates a shift in the emission at 495 nm after PEG coating. Modified carbon dots were introduced into thermo-responsive pNIPAM microgels. The resultant pNIPAM-CQDs@PEG hybrid system exhibits interesting fluorescent properties. Transmission electron microscopy (TEM), fluorescence microscopy, and energy-dispersed X-ray (EDX) spectroscopy confirm the incorporation of CQDs particles into the microgels. Finally, dynamic light scattering (DLS) analysis confirms that the further hybrid microgels based in pNIPAM are thermo-responsive, with a transition temperature similar to that for a system with an ionic component.