Fabrication of PMMA thin film and its optical and photocatalytic activity

Abstract

In this study, the PMMA thin film is fabricated using drop casting method and its optical studies were done using UV/VIS/NIR spectroscopy. The absorption spectrum of thin film showed maximum absorption at 320 nm and the corresponding optical band-gap calculated is 2.83 eV. ATR-IR spectrum gives the different bond stretching and vibrational modes and confirms the presence of different bonds. Its Photoluminescence (PL) study gives a blue emission, observed at 432 nm also denoted by CIE 1931 curve. The optical band-gap calculated from PL is 2.87 eV. Further the effect of different excitation wavelength was examined and possible transitions were explained via transition diagram. The fabricated thin film was used in removal of hazardous dye Rhodamine B (RhB) from tap water. The PMMA thin film was able to photo-degrade 94 % of RhB was degraded in 50 min with reaction rate constant k equal to 0.0579 min−1. The thin film can be reused after oven drying for 2 h at 60⁰ C in hot air vacuum oven. The PMMA thin film was used up to 6 cycles and up to 90 % degradation was observed. Since no extra reducing agents (such as NaBH4) were used in this process hence it makes its possible use in environment friendly photocatalytic agent and waste water treatment.