Spin coated cellulose nanocrystal/silver nanoparticle films

In this study, thin films of cellulose nanocrystals (CNC) and silver nanoparticles (Ag) were assembled ondifferent substrates by spin coating. The effect of substrates, deposition parameters, and nanocrystal mod-ification on the topographical and hydrophilic properties of the obtained layers was investigated. Diluteconcentrations of pristine cellulose nanocrystals (CNC) and surfactant modified crystals (s-CNC) wereused in order to evaluate the effect of modification and concentration on the uniformity of the spin coatedcellulose/silver layers. Morphological investigations by field emission scanning electron microscopy andatomic force microscopy were performed in order to prove the uniformity of the obtained films, whilethe wettability of different surfaces were studied and correlated to the cellulose modification and con-tent. The ability of s-CNC to form a stable dispersion in chloroform permits the formation of a uniformcellulose film on the substrate surfaces generating regular films during the spin coating process. Topo-graphical investigations show, on the other hand, that the CNC/Ag suspension produces a non-uniformdistribution. These effects can be mainly attributed to the surfactant action rather than to the chemicaland electrical properties of the substrate surface. Finally, contact angle studies, underline the hydrophilicnature of s-CNC/Ag based films highlighting that the wettability properties are strongly influenced bythe cellulose nanocrystal nature.