Hard and Transparent Films Formed by Nanocellulose–TiO2 Nanoparticle Hybrids

Abstract

The formation of hybrids of nanofibrillated cellulose and titania nanoparticles in aqueous media has been studied. Their transparency and mechanical behavior have been assessed by spectrophotometry and nanoindentation. The results show that limiting the titania nanoparticle concentration below 16 vol% yields homogeneous hybrids with a very high Young’s modulus and hardness, of up to 44 GPa and 3.4 GPa, respectively, and an optical transmittance above 80%. Electron microscopy shows that higher nanoparticle contents result in agglomeration and an inhomogeneous hybrid nanostructure with a concomitant reduction of hardness and optical transmittance. Infrared spectroscopy suggests that the nanostructure of the hybrids is controlled by electrostatic adsorption of the titania nanoparticles on the negatively charged nanocellulose surfaces.

Surface properties of distinct nanofibrillated celluloses assessed by inverse gas chromatography

“…In fact, the spectra of the TEMPO-oxidised cellulose nanofibres showed in the 1500-1800 cm -1 region a band at 1605 cm -1 due to the CO stretching of the ionized form of the acid [31], in addition to a shoulder at ca. 1640 cm -1 due to the OH bending of absorbed water; the characteristic carboxylic acid band at 1720-1730 cm -1 [31] was not detected ( Figure 5). For the enzymatic nanocellulose only the OH bending vibration of water was observed ( Figure 5).…”

Cellulose nanofiber–titania nanocomposites as potential drug delivery systems for dermal applications

“…Noteworthy, different studies generally reported the use of titania nanoparticles for coating cellulose fibers for photocatalytic and antibacterial application [41][42][43][44] . In this study, we developed a new approach using TiO 2 as active ingredient for drug delivery.…”

Steady-shear and viscoelastic properties of cellulose nanofibril–nanoclay dispersions

“…Recent studies have investigated the effects of pulp source (Tanaka et al 2016), fibril dimension and concentration (Agoda-Tandjawa et al 2010), mechanical treatments (Pääkkö et al 2007), ionic strength (Dong et al 2013), pH (Fall et al 2013), as well as addition of amphiphilic molecules (Quennouz et al 2016) on the rheology of CNF dispersions. Additionally, CNFs can also assist in preparation of homogeneous dispersions of a variety of fillers and pigments, such as carbon nanotubes (Hamedi et al 2014), reduced graphene oxide (Duan et al 2016), TiO 2 (Schütz et al 2012), and CaCO 3 (Lourenço et al 2016) nanoparticles.…”