Changes in the optical properties of fullerene C70 in a polyaniline matrix
Abstract
This study investigates the optical properties and aggregation behavior of polyaniline (PANI) and fullerene C70 solutions in N-methyl-2-pyrrolidone (NMP). Refractometry, UV–Vis absorption, and Raman spectroscopy were employed to analyze intermolecular interactions and structural evolution in solution. The refractive index results reveal concentration-dependent increases and slight time-dependent decreases, indicating enhanced polarizability and gradual structural relaxation in PANI/C70 systems. Absorption spectroscopy shows that C70 introduces strong UV absorption while simultaneously modifying the characteristic visible band of PANI, confirming donor–acceptor interactions. Time-dependent spectral changes suggest aggregation of C70 and conformational reorganization of PANI chains. Raman analysis demonstrates that NMP dominates the vibrational response, while subtle spectral differences confirm the presence and stability of dissolved species. The results provide comprehensive insight into solvent-mediated interactions, aggregation mechanisms, and optical behavior of PANI/C70 systems in solution.
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