5 m after the flame [15]. These volatile organic compounds condense

into a thin carbonaceous layer on deposited TiO2 nanoparticles. Flame-based methods for nanoparticle deposition have been investigated since the 1980s [16–21]. In the LFS process, a liquid precursor is fed into a high-temperature flame check details in which the precursor is atomized into small droplets that evaporate in the flame. The precursor material gas decomposes and nucleates forming nanoparticles that can be collected on a moving web. LFS is suitable for deposition of various metal and metal oxide nanoparticles with a relatively narrow and controllable size distribution of nanoparticles with diameters from 2 to 200 nm [20]. The morphology of the deposited nanoparticles can be controlled via process parameters including gas and precursor feed rates, precursor concentration,

distance of the substrate from the burner, and deposition time (web speed) [22]. In this article, we investigate the compressibility of such LFS-deposited TiO2 nanoparticle coating on paperboard by calendering. see more calendering is a traditional surface finishing technique widely used in the paper industry to give the paper surface a smoother and glossier selleck inhibitor look [23]. In calendering nip, paperboard web is compressed between rolls with controllable temperature, pressure, nip time (web speed), and nip roll materials. Compressibility of the nanoparticle coating will affect surface properties

such as wettability. Individual nanoparticle compressibility has been studied [24–26] under high-pressure by X-ray diffraction. However, as far as the authors know, a systematic study of porous nanoparticle coating compressibility has not been presented until now. Methods The reference substrate is a commercial double pigment-coated paperboard (200 g/m2, Stora Enso, Sweden) manufactured with an online coating process that was used as a substrate for the TiO2 LFS nanoparticle deposition. A schematic picture of the LFS deposition process is shown in Figure 1a. Nanoparticle-coated samples were prepared in a roll-to-roll process using Amisulpride coating and laminating pilot line at the Tampere University of Technology (Tampere, Finland) with a constant web speed of 50 m/min. Titanium(IV) isopropoxide (TTIP; 97% pure, Aldrich, St. Louis, MO, USA) dissolved in isopropanol (IPA) was used as a precursor for the TiO2 nanoparticle coatings with a metal ion concentration of 50.0 mg/ml. The precursor was fed into a spray nozzle with a rate of 12.0 ml/min fixed at 6-cm distance from the moving paperboard substrate. Hydrogen (50 l/min) and oxygen (15 l/min) were used for combustion gases in the process. Figure 1 TiO 2 nanoparticle deposition and compression of nanoparticle-coated paperboard.