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Pjanic, P., Yang, L., Teleman, A. & Hersch, R. (2019). Angular Color Prediction Model for Anisotropic Halftone Prints on a Metallic Substrate. Journal of Imaging Science and Technology, 63(4), 040407-1-040407-11
Open this publication in new window or tab >>Angular Color Prediction Model for Anisotropic Halftone Prints on a Metallic Substrate
2019 (English)In: Journal of Imaging Science and Technology, ISSN 1062-3701, E-ISSN 1943-3522, Vol. 63, no 4, p. 040407-1-040407-11Article in journal (Refereed) Published
Abstract [en]

Under specular reflection, non-isotropic halftones such as line halftones printed on an ink-receiving plastic layer superposed with a metallic layer change their colors upon in-plane rotation of the print. This color change is due to the orientation-dependent optical dot gain of the halftone. A strong dot gain occurs when the incident light is perpendicular to the halftone line structure. A color prediction model is proposed which predicts under specular reflection the color of cyan, magenta and yellow line halftones as a function of the azimuthal rotation angle, the incident angle and the line frequency. The model is calibrated by measuring 17 reflectances at the (25 : 25) measurement geometry, with the incident light parallel to the halftone lines. The model has been tested for several azimuthal rotation and incident viewing angles, each time for 125 different cyan, magenta and yellow ink surface coverages.

Keywords
colour, halftone, printing, metallic substrate, prediction model
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:ri:diva-40764 (URN)10.2352/J.ImagingSci.Technol.2019.63.4.040407 (DOI)2-s2.0-85075549172 (Scopus ID)
Available from: 2019-11-19 Created: 2019-11-19 Last updated: 2019-12-04Bibliographically approved
Mo, L., Guo, Z., Wang, Z., Yang, L., Fang, Y., Xin, Z., . . . Li, L. (2019). Nano-Silver Ink of High Conductivity and Low Sintering Temperature for Paper Electronics. Nanoscale Research Letters, 14, Article ID 197.
Open this publication in new window or tab >>Nano-Silver Ink of High Conductivity and Low Sintering Temperature for Paper Electronics
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2019 (English)In: Nanoscale Research Letters, ISSN 1931-7573, E-ISSN 1556-276X, Vol. 14, article id 197Article in journal (Refereed) Published
Abstract [en]

Highly conductive ink with low sintering temperature is important for printed electronics on paper substrate. Silver nanoparticles (Ag NPs) of different average radii ranging from 48 to 176 nm were synthesized by adjusting the Ag+ concentration in the reaction process. The electric resistivity of the Ag NP-based ink film in relation to Ag NP size, sintering temperature, amount of PVP capping agent on Ag NP surface, and morphology evolution of the film during heating process was investigated. It was found that the resistivity of the films reduced very rapidly with increasing particle size due above all to reduced amount of protective agent capping on the Ag NPs. A semi-empirical relationship between the resistivity and the particle size was proposed. With the help of this mathematical expression, one gains both systematic and detailed insight to the resistivity evaluation with regard to the Ag particle size. The optimal electric resistivity of 4.6 μΩ cm was achieved at 140 °C for 10 min which was very close to the resistivity value of bulk Ag (1.58 μΩ cm). Mechanical flexibility of the printed electronics with the Ag NP-based ink on paper substrates was investigated. The prints on the art coated paper exhibited better flexibility compared to that on the photopaper. This might be attributed to the surface coating composition, surface morphology of the paper, and their corresponding ink absorption property. © 2019, The Author(s).

Place, publisher, year, edition, pages
Springer New York LLC, 2019
Keywords
Flexible and printed electronics, Low sintering temperature, Nano-silver, Paper electronics, Electric conductivity, Flexible electronics, Morphology, Particle size, Protective coatings, Silver nanoparticles, Sintering, Surface morphology, Synthesis (chemical), Mathematical expressions, Mechanical flexibility, Nano silver, Printed electronics, Silver nanoparticles (AgNps), Sintering temperatures, Substrates
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-39061 (URN)10.1186/s11671-019-3011-1 (DOI)2-s2.0-85066951728 (Scopus ID)
Note

Funding details: Beijing Municipal Commission of Education; Funding details: Beijing Municipal Commission of Education, KM201810015004; Funding details: National Natural Science Foundation of China, 61474144; Funding details: Beijing Municipal Commission of Education, CIT&TCD201704051; Funding text 1: This work has been financed by NSFC project (61474144), 2018 Beijing Municipal Commission of Education project (KM201810015004), Beijing Municipal Commission of Education 2011 Collaborative Innovation Centre, 2018 Beijing university talents cross training plan (Shipei plan) and 2017 Beijing Municipal Commission of Education Outstanding young scholars (CIT&TCD201704051).

Available from: 2019-06-20 Created: 2019-06-20 Last updated: 2019-06-20Bibliographically approved
Odeberg Glasenapp, A., Alfthan, J., Salmen, L., Stevanic Srndovic, J., Björk, E., Holmqvist, C., . . . Berthold, J. (2019). Next level of corrugated board research. In: 29th IAPRI Symposium on packaging, 2019: Serving society innovative perspectives on packaging. Paper presented at 29th IAPRI Symposium on packaging, 11-14 June, 2019, Enschede, The Netherlands.
Open this publication in new window or tab >>Next level of corrugated board research
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2019 (English)In: 29th IAPRI Symposium on packaging, 2019: Serving society innovative perspectives on packaging, 2019Conference paper, Published paper (Other academic)
Abstract [en]

 For the first time in the Bioeconomy research program at RISE, corrugatedboard has an own research area. Research is building around the main driving forcesin the corrugated board value chain like e-commerce, improved box performance anddigital printing. The main weakness of corrugated board, its moisture sensitivity, isalso addressed.These main driving forces and weaknesses of corrugated board are mirrored in thethemes of this large research program area:Fibre sorption and deformation mechanismsFundamental knowledge on the mechanisms behind moisture sorption and deformation on fibre level is developed to increase moisture and creep resistance throughmodification of paper materials. State of the art methods for characterization ofthe fibre ultra- and nano-structure such as Fourier transform infra-red spectroscopy(FTIR), small angle X-ray scattering (SAXS), and wide angle X-ray scattering (WAXS)give new insights on mechanisms and clarify effects of moisture as well as chemicalmodifications.Papermaking for improved base sheetsConcepts that are explored are fibre-based strength additives produced with novelrefining techniques, and modified ZD-profiles in the sheet for better mechanical properties.Box mechanicsMechanical performance of structures such as corrugated board boxes can be predicted through physically based mathematical modelling by taking the behaviour ofthe constituent materials as well as the geometry into account. Appropriate materialmodels for the corrugated board are identified and finite element models for simulation of corrugated board packaging performance are developed.Tool for inkjet printability on corrugatedThere is a genuine need for improved inkjet printability on corrugated materials thanksto rapid development in e-commerce as well as digitalization along the corrugatedvalue chain. Effective measurement methods and knowledge around ink-substrateinteractions are developed to enable board producers and converters to have effective product development and predictable printability on not only liners but also oncorrugated materials.

Keywords
corrugated board, moisture, box mechanics, inkjet printing, fibre sorption
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:ri:diva-39737 (URN)
Conference
29th IAPRI Symposium on packaging, 11-14 June, 2019, Enschede, The Netherlands
Available from: 2019-08-14 Created: 2019-08-14 Last updated: 2019-08-15Bibliographically approved
Xin, Z., Yan, M., Gu, L., Liu, J., Liu, R., Li, L., . . . Yang, L. (2019). Scalable Fabrication of Conductive Lines by Patterned Wettability-Assisted Bar-Coating for Low Cost Paper-Based Circuits. Advanced Materials Interfaces, 6(10), Article ID 1802047.
Open this publication in new window or tab >>Scalable Fabrication of Conductive Lines by Patterned Wettability-Assisted Bar-Coating for Low Cost Paper-Based Circuits
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2019 (English)In: Advanced Materials Interfaces, ISSN 2196-7350, Vol. 6, no 10, article id 1802047Article in journal (Refereed) Published
Abstract [en]

Patterning technology on the paper based on wettability difference for paper-based devices has attracted significant attention for its low cost, easy degradability, and high flexibility. Here, conductive lines are rapidly prepared by patterned wettability-assisted bar-coating for low cost paper-based circuits. It is found that 7 s plasma treatment time for acquiring wettability difference is optimal, which resulted in not only effective splitting of the liquid film but also highly consistent line width with mask. Moreover, low retention force of hydrophobic surface is imperative for self-confinement of the ink into hydrophilic areas, especially for ink with high solid content. The sheet resistance of patterns can reach 5 Ω ◻ −1 after 980 nm laser sintering when using 50 wt% solid content ink with 110 cP viscosity. The geometries of line patterns, i.e., line width and spacing, can be readily tuned by varying the designed size of mask patterns. As-prepared conductive patterns show good conductivity even after 500 bending cycles at 2 mm bending radius. It is believed that this study will provide deeper understanding of wettability difference-assisted patterning process and represents a general strategy for selective wetting, especially for high viscosity ink.

Place, publisher, year, edition, pages
Wiley-VCH Verlag, 2019
Keywords
Coated paper, Paper based devices, Patterning technology, Printed electronics, Substrate surface
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:ri:diva-38519 (URN)10.1002/admi.201802047 (DOI)2-s2.0-85063997604 (Scopus ID)
Available from: 2019-04-29 Created: 2019-04-29 Last updated: 2019-07-01Bibliographically approved
Mo, L., Guo, Z., Zhang, Q., Fang, Y., Xin, Z., Hu, K., . . . Chen, Z. (2019). Silver Nanoparticles Based Ink with Moderate Sintering in Flexible and Printed Electronics. International Journal of Molecular Sciences, 20(9)
Open this publication in new window or tab >>Silver Nanoparticles Based Ink with Moderate Sintering in Flexible and Printed Electronics
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2019 (English)In: International Journal of Molecular Sciences, ISSN 1422-0067, E-ISSN 1422-0067, Vol. 20, no 9Article in journal (Refereed) Published
Abstract [en]

Printed electronics on flexible substrates has attracted tremendous research interest research thanks its low cost, large area production capability and environmentally friendly advantages. Optimal characteristics of silver nanoparticles (Ag NPs) based inks are crucial for ink rheology, printing, post-print treatment, and performance of the printed electronics devices. In this review, the methods and mechanisms for obtaining Ag NPs based inks that are highly conductive under moderate sintering conditions are summarized. These characteristics are particularly important when printed on temperature sensitive substrates that cannot withstand sintering of high temperature. Strategies to tailor the protective agents capping on the surface of Ag NPs, in order to optimize the sizes and shapes of Ag NPs as well as to modify the substrate surface, are presented. Different (emerging) sintering technologies are also discussed, including photonic sintering, electrical sintering, plasma sintering, microwave sintering, etc. Finally, applications of the Ag NPs based ink in transparent conductive film (TCF), thin film transistor (TFT), biosensor, radio frequency identification (RFID) antenna, stretchable electronics and their perspectives on flexible and printed electronics are presented.

Keywords
biosensor, flexible and printed electronics, moderate sintering, photonic sintering, protective agent, silver nanoparticles, substrate modification, transparent conductive film
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-39877 (URN)10.3390/ijms20092124 (DOI)
Available from: 2019-08-30 Created: 2019-08-30 Last updated: 2019-08-30Bibliographically approved
Lindberg, A., Alfthan, J., Pettersson, H., Flodberg, G. & Yang, L. (2018). Mechanical performance of polymer powder bed fused objects: FEM simulation and verification. Additive manufacturing, 24, 577-586
Open this publication in new window or tab >>Mechanical performance of polymer powder bed fused objects: FEM simulation and verification
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2018 (English)In: Additive manufacturing, ISSN 2214-8604, Vol. 24, p. 577-586Article in journal (Refereed) Published
Abstract [en]

Additive manufacturing (3D printing) enables the designing and producing of complex geometries in a layer-by-layer approach. The layered structure leads to anisotropic behaviour in the material. To accommodate anisotropic behaviour, geometrical optimization is needed so that the 3D printed object meets the pre-set strength and quality requirements. In this article a material description for polymer powder bed fused also or selective laser sintered (SLS) PA12 (Nylon-12), which is a common 3D printing plastic, was investigated, using the Finite Element Method (FEM). The Material Model parameters were obtained by matching them to the test results of multipurpose test specimens (dumb-bells or dog bones) and the model was then used to simulate/predict the mechanical performance of the SLS printed lower-leg prosthesis components, pylon and support. For verification purposes, two FEM designs for a support were SLS printed together with additional test specimens in order to validate the used Material Model. The SLS printed prosthesis pieces were tested according to ISO 10328 Standard. The FEM simulations, together with the Material Model, was found to give good estimations for the location of a failure and its load. It was also noted that there were significant variations among individual SLS printed test specimens, which impacted on the material parameters and the FEM simulations. Hence, to enable reliable FEM simulations for the designing of 3D printed products, better control of the SLS process with regards to porosity, pore morphology and pore distribution is needed.

Keywords
additive manufacturing, 3D printing, selective laser sintering, finite element method, material model
National Category
Materials Engineering
Identifiers
urn:nbn:se:ri:diva-36296 (URN)10.1016/j.addma.2018.10.009 (DOI)2-s2.0-85056189717 (Scopus ID)
Available from: 2018-11-15 Created: 2018-11-15 Last updated: 2019-06-27Bibliographically approved
Flodberg, G., Pettersson, H. & Yang, L. (2018). Pore analysis and mechanical performance of selective laser sintered objects. Additive Manufacturing, 24, 307-315
Open this publication in new window or tab >>Pore analysis and mechanical performance of selective laser sintered objects
2018 (English)In: Additive Manufacturing, ISSN 2214-8604, Vol. 24, p. 307-315Article in journal (Refereed) Published
Abstract [en]

In this work, systematic studies were carried out on SLS (selective laser sintering) printed samples, with two different geometries, standard test samples dumb-bells (dog bones) and tubes (Ø 30 mm and 150 mm long), consisting of two different materials, viz. PA12 (polyamide) with and without the addition of carbon fibres (CFs). These samples were tested according to their respective ISO standards. The standard test samples exhibited relatively small differences with regards to printing directions when PA12 was used alone. Their tensile strengths (σm) were approx. 75%–80% of the injection-moulded sample. The addition of carbon fibres significantly enhanced the tensile strengths, namely 50% greater for the vertically printed test sample and more than 100% greater for the horizontally printed samples, compared to the respective objects consisting of PA12 alone. The strong difference in printing directions can be attributed to the orientation of the carbon fibres. Mechanical tests on the SLS printed tubes confirmed the trends that were found in the standard test samples. Porosity and pore structure inside the SLS printed tubes were studied by combining optical microscopy and X-ray microtomography with image analysis. It was found that porosity was a general phenomenon inside the SLS printed samples. Nevertheless, there were significant differences in porosity, which probably depended on the properties of the materials used, both with and without carbon fibres, thus causing significant differences in light absorption and heat conductivity. The printed samples made of PA12 alone possessed quite a high level of porosity (4.7%), of which the size of the biggest pore was hundreds of microns. The twenty biggest pores with an average size of 75*104 ÎŒ m3 accounted for 43% of the total porosity. However, the porosity of the printed samples made from PA12 + CF was only 0.68%, with the biggest pore being only tens of microns. The corresponding average pore size of the 20 biggest pores was 72*103 ÎŒ m3, which was one order of magnitude smaller than the printed samples made from PA12 alone. Pores inside the SLS printed samples were probably responsible for a spread in the mechanical properties measured, e.g. tensile strengths, tensile (Young’s) modulus, strain at break, etc. The ratios of their standard deviations to their corresponding mean values in the standard test samples could probably be used as an indicator of porosity, i.e. the bigger the ratio, the higher the porosity.

Place, publisher, year, edition, pages
Elsevier B.V., 2018
Keywords
additive manufacturing, 3D printing, selective laser sintering, porosity, x-ray microtomography, image analysis
National Category
Materials Engineering
Identifiers
urn:nbn:se:ri:diva-35531 (URN)10.1016/j.addma.2018.10.001 (DOI)2-s2.0-85054850953 (Scopus ID)
Available from: 2018-10-30 Created: 2018-10-30 Last updated: 2019-06-27Bibliographically approved
Xin, Z., Liu, J., Gu, L., Fang, Y., Mo, L. & Yang, L. (2018). Surface energy guided patterning for printed electronics applications. In: 45th International IARIGAI conference: . Paper presented at 45th International IARIGAI conference, 3-7 October 2018, Warsaw, Poland.
Open this publication in new window or tab >>Surface energy guided patterning for printed electronics applications
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2018 (English)In: 45th International IARIGAI conference, 2018Conference paper, Published paper (Other academic)
Abstract [en]

We demonstrated patterning method for silver nanoparticle ink by wire-wound rod coating on commercial paper substrate. The hydrophobic and hydrophilic zones (patterns) on the paper surface were created by combining coating of hydrophobic dispersion with selective plasma treatment using a mask. Thanks to the surface energy difference in different zones, the silver nanoparticle ink self-aligned to form desired patterns, e.g. a matrix of lines of 0.5 mm wide with 0.3 mm spacing.

Keywords
printed electronics, rod coating, surface energy, printing dynamics
National Category
Electrical Engineering, Electronic Engineering, Information Engineering Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:ri:diva-39914 (URN)
Conference
45th International IARIGAI conference, 3-7 October 2018, Warsaw, Poland
Available from: 2019-09-17 Created: 2019-09-17 Last updated: 2019-09-17Bibliographically approved
Yang, L., Liu, J. & Wei, X. (2017). A model of inkjet printing on porous substrates incorporating droplet impact. In: Gane P (Ed.), 44th International Research Conference of iarigai: Proceedings. Paper presented at 44th International Research Conference of iarigai: Advances in Printing and Media Technology held in Fribourg, Switzerland, 10-13 September 2017 (pp. 3-6). Darmstadt: International Association of Research Organizations for the Information, Media and Graphic Arts Industrie (IARIGAI), 44
Open this publication in new window or tab >>A model of inkjet printing on porous substrates incorporating droplet impact
2017 (English)In: 44th International Research Conference of iarigai: Proceedings / [ed] Gane P, Darmstadt: International Association of Research Organizations for the Information, Media and Graphic Arts Industrie (IARIGAI), 2017, Vol. 44, p. 3-6Conference paper, Published paper (Refereed)
Abstract [en]

A model of inkjet printing dynamics has been developed that enables a comprehensive view to be obtained of the relationships between the characteristics of the ink droplet (volume, striking speed, viscosity and surface tension), substrate properties and interactions between the ink and the substrate. Simulations based on the three equations that are the major results of the model have provided an understanding of the basics of inkjet printing. Pressure profiles resulting from ink-striking by ink droplets of different volumes and jetting speeds have been obtained. The time duration of the striking process was in the order of microsecond and the peaks of the striking pressure were solely dependent on the jetting velocities, while the duration time of the striking processes was dependent only on the droplets volumes. The penetration length (depth) was heavily dependent on the contact angle. For a coated surface of small pores, the initial penetration depth was 0.26 micron when the striking speed was 30m/s. For a larger pore, the corresponding depth was 1.30 micron.

Place, publisher, year, edition, pages
Darmstadt: International Association of Research Organizations for the Information, Media and Graphic Arts Industrie (IARIGAI), 2017
Keywords
ink jet printing, ink penetration, ink properties, ink transfer, modelling, pore size
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:ri:diva-32970 (URN)978-3-9870704-7-1 (ISBN)
Conference
44th International Research Conference of iarigai: Advances in Printing and Media Technology held in Fribourg, Switzerland, 10-13 September 2017
Available from: 2018-01-03 Created: 2018-01-03 Last updated: 2019-06-17Bibliographically approved
Zhang, W., Wang, Q., Feng, X., Yang, L., Wu, Y. & Wei, X. (2017). Anthracene-based derivatives: Synthesis, photophysical properties and electrochemical properties. Chemical Research in Chinese Universities, 33(4), 603-610
Open this publication in new window or tab >>Anthracene-based derivatives: Synthesis, photophysical properties and electrochemical properties
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2017 (English)In: Chemical Research in Chinese Universities, ISSN 1005-9040, E-ISSN 2210-3171, Vol. 33, no 4, p. 603-610Article in journal (Refereed) Published
Abstract [en]

A series of anthracene-based derivatives, namely, 9-(4-phenyl)anthracene(1), 9-(4-phenylethynyl)-anthracene(2) and 9, 10-bis(phenylethynyl)anthracene(3), was synthesized by the Suzuki/Sonogashira cross-coupling reactions in good yields. These compounds were fully characterized by X-ray crystallography, thermogravimetric analysis(TGA), differential scanning calorimetry(DSC), UV-Vis absorption and fluorescence(FL) spectroscopy, as well as density functional theory(DFT) calculations. Single-crystal X-ray analysis revealed that the packing structures were influenced by the terminal substitutions. All the compounds exhibited high thermal stability(Td=221—484 °C) and blue emission with a high quantum yield(Ωf =0.20—0.75). As the number of substituents increased, the decomposition temperatures(Td) of these compounds increased in the following order: 1<2<3. Experiments on the photophysical properties revealed that different substituents strongly affected the optical properties. In particular, compound 1b with the electron-withdrawing group(—CHO) exhibited a larger Stokes shift(113 nm) than the other compounds. Investigation of the electrochemical properties of these compounds showed that the HOMO-LUMO energy gaps(Egap) decreased obviously as the degree of conjugation increased.

Keywords
anthracene, derivative, blue-emitting material, photophysical properties
National Category
Materials Engineering
Identifiers
urn:nbn:se:ri:diva-30336 (URN)10.1007/s40242-017-6431-4 (DOI)2-s2.0-85025083693 (Scopus ID)
Available from: 2017-08-18 Created: 2017-08-18 Last updated: 2019-06-17Bibliographically approved
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