Structural, thermal and optical properties of $${\hbox {Cu}}^{2+}$$ doped methacrylic acid–ethyl acrylate (MAA:EA) copolymer films

Pure and \({\hbox {Cu}}^{2+}\) doped methacrylic acid–ethyl acrylate (MAA:EA) copolymer films were prepared using the solution cast technique. The amorphous feature of the copolymer was depicted using X-ray diffraction scans and degree of crystallinity was found to vary with increasing doping content. UV–Vis absorption spectra in the wavelength region 200–900 nm were used to evaluate the optical properties like direct band gap, indirect band gap and absorption edge. The optical band gap decreased with the increase of mol% of \(\hbox {Cu}^{2+}\) ions. Fourier transform infrared spectral studies on pure MAA:EA and \(\hbox {Cu}^{2+}\) ions-doped films revealed the vibrational changes that occurred due to the effect of dopant salt in the copolymer. Thermal properties of these films were investigated by employing differential scanning calorimetry and thermogravimetric analysis. The variation in film morphology was examined by scanning electron microscopy. Electron paramagnetic resonance (EPR) spectra of all the doped samples exhibited signals due to \(\hbox {Cu}^{2+}\) ions with the effective g-values \(g_{\Vert } = 2.177\) and \(g_{\bot }= 2.058\). The observed variation in the EPR signal intensity is due to the isolated and aggregated copper ions. The photoluminescence spectra of \(\hbox {Cu}^{2+}\) ions-doped MAA:EA copolymer exhibited four emission peaks at 480 (blue), 579 (yellow), 604 (red) and 671 nm (red).