For the preparation of electrically conductive composites, various combinations of cellulose and conducting materials such as polymers, metals, metal oxides and carbon have been reported. The conductivity of these cellulose composites reported to date ranges from 10-6 to 10 3 S cm-1. Cellulose nanocrystals (CNCs) are excellent building blocks for the production of high added value coatings. The essential process steps for preparing such coatings, i.e. surface modification of CNCs dispersed in water and/or alcohol followed by application of the dispersion to substrate samples using dip coating, are low cost and easily scalable. Here, we present coatings consisting of Ag modified CNCs that form a percolated network upon solvent evaporation. After photonic sintering, the resulting coatings are electrically conductive with an unprecedented high conductivity of 2.9 9 10 4 S cm-1. Furthermore, we report the first colloidal synthesis that yields CNCs with a high degree of Ag coverage on the surface, which is a prerequisite for obtaining coatings with high electrical conductivity.

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Featured Application: A unique set-up for real-time monitoring of the size of nanoparticles during bottom-up liquid phase synthesis is presented in this article. The analysis method applied to study the size of dispersed nanoparticles during synthesis is dynamic light scattering (DLS). In contrast to conventional DLS, the DLS set-up presented in this article comprises a modulated 3D cross correlation geometry, and therefore allows accurate measurements of particle size in flow at flow rates of at least up to 17 mL·min −1 . This is essential for obtaining real-time information on the size of the dispersed nanoparticles. The DLS system could be connected to reactors of various sizes using the analysis loop presented in this article, which is coupled to a flow cell in the DLS set-up. Thus, the DLS set-up presented here is suited to study the nucleation and growth of nanoparticles in dispersion, facilitates a rational scale-up, and allows intervention in the production process of nanoparticle dispersions to minimize the number of off-spec batches.Abstract: To tailor the properties of nanoparticles and nanocomposites, precise control over particle size is of vital importance. Real-time monitoring of particle size during bottom-up synthesis in liquids would allow a detailed study of particle nucleation and growth, which provides valuable insights in the mechanism of formation of the nanoparticles. Furthermore, it facilitates a rational scale-up, and would enable adequate intervention in the production process of nanoparticle dispersions to minimize the number of off-spec batches. Since real-time monitoring requires particle size measurements on dispersions in flow, conventional dynamic light scattering (DLS) techniques are not suited: they rely on single scattering and measure the Brownian motion of particles dispersed in a liquid. Here, we present a set-up that allows accurate measurements in real-time on flowing dispersions using a DLS technique based on modulated 3D cross-correlation. This technique uses two simultaneous light scattering experiments performed at the same scattering vector on the same sample volume in order to extract only the single scattering information common to both. We connected the reactor to a flow-cell in the DLS equipment using a tailor-made analysis loop, and successfully demonstrated the complete set-up through monitoring of the size of spherical silica nanoparticles during Stöber synthesis in a water-alcohol mixture starting from the molecular precursor tetraethyl orthosilicate.

The application of nanoparticles (NPs) in food products is ever increasing. For consumer safety it is essential to know the human oral bioavailability of these NPs. In the present study, a combination of physiologically relevant in vitro and ex vivo models are presented, which combined are considered to predict human intestinal digestion and absorption of NPs more accurately than commonly applied animal or cellular studies.First, a computer controlled dynamic in vitro gastrointestinal model (tiny-TIM) is used for simulation of the digestive processes upon gastro-intestinal passage of non-biodegradable aminated, carboxylated, or unmodified fluorescent polystyrene NPs (PS-NPs). Then, the pretreated (digested) PS-NPs were consequently evaluated for absorption using ex vivo porcine intestinal tissue.In this study, we found that the digestion of non-biodegradable aminated, carboxylated, or unmodified fluorescent polystyrene NPs (PS-NPs) leads to different bioaccessible concentrations, with unmodified PS-NP concentrations being 3.5-and 4.5-fold lower than the aminated and carboxylated PS-NPs, respectively. In addition, we observed a reduced absorption of PS-NPs by ex vivo porcine intestinal tissue from the digestive matrix when compared to the absorption of their undigested counterparts in Krebs-Ringer Bicarbonate (KRB) buffer. The current results prove that oral absorption of PS-NPs in humans is to be expected in vivo. In the risk assessment of potential oral exposure to NPs in food products it is therefore key that the exposure and hazard assessment are performed with the NPs in physiologically relevant conditions, since this may influence the absorption and hazard properties of the NPs.