Study on the Preparation and Characteristics of Cellulose/Silver Iodide Nanocomposite Film

In this study, the structure and properties of an organic-inorganic composite material prepared from cellulose doped with fine particles of silver iodide (AgI) were examined. The preparation of the composite involved the complexation of cellulose with polyiodide ions, such as I- and 13-, by immersion in iodine/potassium iodide (I2/KI: 0.2, 0.4, 0.6, 0.8, 1.0 M) or potassium iodide (KI: 0.6, 1.2, 1.8, 2.4, 3.0 M) aqueous solutions followed by reaction in a silver nitrate (AgNO3:1.0 M) aqueous solution. These procedures resulted in the in situ formation of fine β-AgI particles within the cellulose matrix. The characteristics and conductivities of prepared cellulose/silver iodide (AgI) nanocomposite films with different I2/KI and KI concentrations were investigated. AgI particle formation and aggregation increased on increasing I2/KI and KI concentrations as determined by SEM. X-ray results showed that KI could penetrate the cellulose crystal region and form AgI particles. The electrical conductivities of nanocomposite films treated with KI were higher than that of I2/KI at < 1.0 M of I2/KI and 3 M of KI, although the weight gain by AgI formation was lower than that of I2/KI. This was also attributed to the formation of smaller AgI particles and crystal defects. Highest electrical conductivity (3.8 x 10(-7) Ω(-1) cm(-1)) was obtained from the cellulose films (1.25 x 10(-11) Ω(-1) cm(-1)) treated with the aqueous solutions of 1.0 M I2/KI and 1.0 M AgNO3.