A Study on the Impact of the Adhesion of Penicillium expansum on the Physicochemical Surface Properties of Cedar Wood

The sessile drop technique was used to investigate the evolution of the physicochemical properties of cedar wood as a function of contact time with the Penicillium expansum spores. The most important finding showed that the impact of different contact periods (2, 4, 6, 8, 10, and 24 hr) on the wood surface were very indicative. In fact, after 2 hr of contact, the results have shown a significant impact of the bioadhesion of spores to the substrate on both the hydrophobic character (theta(W) = 108.5 degrees; Delta Giwi = -28.25 mJ/m(2)), the electron donor (gamma(-) = 13.63 mJ/m(2)), and the electron acceptor (gamma(+) = 4.35 mJ/m(2)) parameters that were significantly reduced compared to the initial wood (theta(W) = 118.5 degrees; Delta Giwi = -6.29 mJ/m(2); gamma(-) = 32.1 mJ/m(2); and gamma(+) = 9.1 mJ/m(2)). In addition, this decrease of parameters continued over time to stabilize after 10 hr of contact. Indeed, after 24 hr, the acid/base properties were almost zero and the contact angle with water decreased to 30 degrees. Moreover, it was found that the coefficient of correlation (r(2)) was strong between the contact angle with water, the surface energy, and the electron acceptor character with the contact time parameter with values (r(2) = 0.65), (r(2) = 0.79), and (r(2) = 0.68), respectively.