title: A facile and green method to hydrophobize films of cellulose nanofibrils and silica by laccase-mediated coupling of nonpolar colloidal particles.
abstract: Hydrophobic particles based on dodecyl 3,4,5-trihydroxybenzoate (LG) were coupled onto the surface of cellulose nanofibrils (CNFs) and silica by treatment with a multicomponent colloidal system (MCS) derived from the laccase-mediated reaction of LG in the presence of a sulfonated lignin (SL). Surface modification upon treatment with MCS was monitored in situ and in real time by quartz crystal microgravimetry. The colloidal stability of MCS and its components in water was followed by measuring space- and time-resolved light transmission and back scattering. The sulfonated lignin increased dispersion stability and reduced the characteristic MCS particle size [from ≈4 to ≈80 nm, according to AFM and dynamic light scattering (DLS)]. It also facilitated the surface enzymatic reaction that led to adsorption and coupling of MCS onto CNFs and silica surfaces. The combined effect of reduced surface energy and surface roughness by MCS treatment produced an increase in water contact angle on CNFs and silica of about 90 and 80°, respectively. Surface pretreatment with chitosan further increased the extent of MCS adsorption on the surfaces. This method represents a sustainable alternative to traditional approaches for cellulose hydrophobization and a step forward in implementing green routes for surface modification.
authors.affiliation: Textile and Paper Engineering Department, Universitat Politècnica de Catalunya (UPC, BarcelonaTech), Colom 11, 08222 Terrassa (Spain); Department of Forest Products Technology, School of Chemical Technology, Aalto University, P.O. Box 16300, 00076 Aalto, Espoo (Finland). oriol.cusola@etp.upc.edu.
authors.forename: Oriol
authors.initials: O
authors.lastname: Cusola
authors.forename: M Blanca
authors.initials: MB
authors.lastname: Roncero
authors.forename: Teresa
authors.initials: T
authors.lastname: Vidal
authors.forename: Orlando J
authors.initials: OJ
authors.lastname: Rojas
mesh_terms: D002482:Cellulose / Q000737:chemistry*; D003102:Colloids / Q000737:chemistry*; D005707:Gallic Acid / Q000737:chemistry*; D055772:Green Chemistry Technology; D057927:Hydrophobic and Hydrophilic Interactions; D042845:Laccase / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D057139:Nanofibers / Q000737:chemistry* / Q000648:ultrastructure; D009391:Nephelometry and Turbidimetry; D010316:Particle Size
chemical_list: D003102:Colloids; D005707:Gallic Acid; D002482:Cellulose; D042845:Laccase
keywords: adsorption; biocatalysis; enzymes; hydrophobization; nanoparticles