TEMPO nanofibrillated cellulose as template for controlled release of antimicrobial copper from PVA films

TEMPO nanofibrillated cellulose (TNFC) was used in different concentrations (0, 30, 50, and 70 wt%, all based on the mass of cellulose-copper hybrid material) as template to synthesize copper nanoparticles from copper sulfate; the resulting hybrid material was mixed with polyvinyl alcohol to prepare films. The final composite films were evaluated effectively in terms of their antimicrobial properties against Escherichia coli DH5α and in terms of the copper release from the films on deionized water. Copper concentration was determined by inductively coupled plasma optical emission spectroscopy. The results indicate that increasing the cellulosic material concentration will facilitate the control of copper release from the films. Data regarding to copper release rate was modeled by empirical models; the results indicate that copper release obeys the power law when TNFC is at a low concentration (≤30 %), and presents an exponential behavior when TNFC concentration increase up to 70 % (coefficient R² is 0.9951).