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- Alecrim, Viviane, et al.
(author)
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Exfoliated Layered Materials for Digital Fabrication
- 2015
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In: NIP & Digital Fabrication Conference. ; , s. 192-194
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Conference paper (peer-reviewed)abstract
- We introduced an exfoliation method of MoS2 in a 3% solution of sodium dodecyl surfactant at high concentration (i.e. 2 g/L). The bulk MoS2 was thinned by mechanical exfoliation between sand papers and the resulting powder was used to prepare dispersions by liquid exfoliation through probe sonication. The resulting dispersion consisted of very thin MoS2 nanosheets in surfactant solution with average lateral size around 126 nm. This may be interesting for applications in inkjet printed electronics.
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| 4. |
- Alecrim, Viviane, 1981-, et al.
(author)
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Flexographic ink film’s resistance to inkjet ink’s solvent flow in Hybrid Printing
- 2011
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In: International Conference on Digital Printing Technologies. - : The Society for Imaging Science and Technology. - 9780892082964 ; , s. 79-85
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Conference paper (peer-reviewed)abstract
- Through Darcy’s permeability coefficient, K, one can evaluate the resistance of a flexographic ink film to the solvent penetration of an inkjet ink through a paper substrate. This resistance plays an important role for the print quality in hybrid printing applications where flexography and inkjet printing are combined. If this resistance is too high, K→0, the inkjet ink’s solvent would not penetrate into the substrate and ink smearing would occur resulting in poor printability.Paper substrates were printed in a flexographic laboratory printing press. The flexographic printing dot area was varied to evaluate the influence of the full tone and halftone areas on K. These print outs were employed as filters for pigmented inkjet water based inks in a filtration setup. The inks had different pigment’s mean particle size which allowed us to address the influence of this parameter on the filter cake build up and consequently, its impact on K. The dot area had indeed an impact in the ink’s solvent penetration as we observed that the higher the dot area, the lower the K value, meaning that the resistance for ink´s solvent flow was higher. The pigment’s mean particle size also showed influence on K, as we observed that the bigger the pigment particles, the higher the K. The substrates were selected after a screening based on inkjet ink absorption speed evaluated through a print rub off test and line width measurements of printed lines.We also printed the pre-printed flexography images using a KM 512 piezoelectric printing head and one of the inks used during filtration to evaluate the inkjet printing quality for this hybrid printing approach. We observed wider, less blurry and ragged lines with increased dot area. No ink smearing was observed for the print outs.
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| 7. |
- Niga, Petru, et al.
(author)
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Hybrid printing : paper media for combined flexographic and inkjet printing
- 2012
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In: Conference proceedings International Paper Physics Conference. - Stockholm : Innventia. ; , s. 79-81
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Conference paper (other academic/artistic)abstract
- Hybrid printing combining inkjet technology with flexography can be used to add customer specific information into the production of packaging and print. However, in order to improve print quality, a comprehensive understanding of the mechanisms governing print quality is required. In this work, inkjet printing using three aqueous inkjet inks was performed on top of flexographic printouts on four paper substrates. For comparative reasons, inkjet printouts were made on the four papers as well. The flexographic film contained tone values ranging from 0 to 100% ink coverage. Line width and print density of the inkjet printouts were evaluated. It was found that paper characteristics such as surface energy, porosity, absorption coefficient and surface roughness play an important role in defining the final print quality. These findings are further supported by micrograph images.
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| 9. |
- Zhang, Renyun, et al.
(author)
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Thermally reduced kaolin-graphene oxide nanocomposites for gas sensing
- 2015
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 5, s. Art. no. 7676-
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Journal article (peer-reviewed)abstract
- Highly sensitive graphene-based gas sensors can be made using large-area single layer graphene, but the cost of large-area pure graphene is high, making the simpler reduced graphene oxide (rGO) an attractive alternative. To use rGO for gas sensing, however, require a high active surface area and slightly different approach is needed. Here, we report on a simple method to produce kaolin-graphene oxide (GO) nanocomposites and an application of this nanocomposite as a gas sensor. The nanocomposite was made by binding the GO flakes to kaolin with the help of 3-Aminopropyltriethoxysilane (APTES). The GO flakes in the nanocomposite were contacting neighboring GO flakes as observed by electron microscopy. After thermal annealing, the nanocomposite become conductive as showed by sheet resistance measurements. Based on the conductance changes of the nanocomposite films, electrical gas sensing devices were made for detecting NH3 and HNO3. These devices had a higher sensitivity than thermally annealed multilayer GO films. This kaolin-GO nanocomposite might be useful in applications that require a low-cost material with large conductive surface area including the demonstrated gas sensors.
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