Optical and Dielectric Properties of PMMA (Poly(methyl methacrylate))/Carbon Dots Composites

The optical and the dielectric properties of an original nanocomposite based on the incorporation of carbon dots (C-dots) in poly(methyl methacrylate) (PMMA) at several filler loading were studied. The optical characterization demonstrated the preservation of the excitation dependent intense emission of the C-dots in the polymer, ascribed to the presence of organic fluorophores formed during the nanoparticle synthesis. The composite PMMA/C-dots dielectric properties were investigated in the frequency range from 40 Hz to 1 MHz and over the temperature range from 200 to 400 K. The dielectric response was obtained using the complex permittivity or the modulus formalisms, depending on the concentration of filler in the polymer matrix. A relaxation phenomenon was induced by the incorporation of the C-dots in the PMMA matrix. In addition, both the real and imaginary parts of the dielectric permittivity and electric modulus changed with the volume fraction of the C-dots, suggesting that the presence of the fillers greatly affect the dielectric properties of the polymer matrix because of polarization phenomenon induced by the nanoparticles. (C) 2018 Society of Plastics Engineers