Optically transparent and lightweight nanocomposite substrate of poly(methyl methacrylate-co-acrylonitrile)/MWCNT for optoelectronic applications: an experimental and theoretical insight

The electrically conductive and optically transparent flexible nanocomposites made of polymers and multi-walled carbon nanotube (MWCNT) have the potential to be used as a transparent substrate for optoelectronic applications. In this investigation, we have fabricated a series of nanocomposites of MWCNT, used as conductive filler, with a copolymer of methyl methacrylate and acrylonitrile as a matrix, and solution blending method was used to achieve suitable dispersions. The MWCNT content varied sequentially in these nanocomposite thin films. A detailed study about the dispersion of MWCNTs in the matrix was done by attenuated total reflectance-infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The surface roughness is continuously increasing with an increase in the amount of conductive filler in the polymer matrix. However, it never exceeds 10 nm, which is very small compared to the MWCNT length, and also confirmed nearly complete embedding of conducting filler in the insulating matrix. The diffusion coefficient of nanocomposite was investigated for O-2 and H2O with Molecular Dynamics simulations and found to decrease with increasing load percentage of MWCNT. The thin film's optical transmittance and electrical conductivity are characterized thoroughly. An optimized formulation of nanocomposite with 0.25% MWCNT has shown enhanced conductivity of 10(-2) S/cm (semiconductive range) with similar to 94% optical transparency at 550 nm.