Browsing by Author "Kosmala, A."

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    Development of high concentrated aqueous silver dispersion for inkjet printing on ceramic substrates
    (2012-02-15T00:00:00Z) Kosmala, A.; Zhang, Q.; Wright, R.; Kirby, Paul B.
    In this paper, the formulation of a high Ag loading (45 wt %) aqueous ink and its subsequent printing on three different ceramic substrates were reported. Monodispersed Ag nanoparticles with a size down to 10 nm were successfully synthesized in aqueous medium. These nanoparticles were then successfully dispersed up to 45 wt% in aqueous medium with the aid of a co-polymer, Pluronic F127. The printed tracks show the electrical conductivity of 3μΩcm close to the value of silver bulk (1.6 μΩcm). The use of high solid loading inks reduces the number of printed layers required for thick, dense and conductive film thus leading to the reduction of the costs, and high efficiency of the printing process. High solid loading also results in the finer printed features. The effect of substrates, printing temperature and dot spacing on the size and morphology of printed silver features was investigated. Increasing the dot spacing together with the substrates temperature resulted in the limited ink spreading, hence narrow printed line and improved geometry of printed patte
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    Development of high loading Ag nanoparticle inks for inkjet printing and Ag nanowire dispersions for conducting and transparent coatings
    (Cranfield University, 2012-03) Kosmala, A.; Zhang, Qi; Kirby, Paul B.
    The work presented in this thesis focuses on the synthesis of nanomaterials, formulation and printing of Ag nanoparticle and nanowire inks for two distinct applications: a) inkjet printing of Ag nanoparticle films on ceramic substrates with the aim of providing a smaller size of printed feature at lower cost than that can be obtained with the conventionally used screen printing, and b) Ag nanowires films prompted by the wide quest of electronics industry for materials with increased flexibility, lower cost and higher transmittance to replace indium tin oxide. Ag nanoparticles with a size of 50 nm were successfully synthesized and dispersed in aqueous medium. Two preparation routes were compared in order to distinguish the effects of solvents treatment of particles and their influence on the suspension characteristics including Ag loading, rheology, surface tension and later the electrical film properties. The co-polymer Pluronic F127 was found to be an effective as a stabiliser leading to the formulation of high silver loading in inks. The processing and characterization of silver films was performed. The aim was to reduce the number of layers in the silver nanoparticles film by increasing the thickness of a single layer with the goal of obtaining a dense and conductive film. An increase in the Ag loading, from 5 wt % to 45 wt % favoured the achievement of denser and thicker film with one layer printing. Addition of SiO2 to the ink formula resulted in denser structure and better adhesion of the printed track then the one without SiO2. A new method for improving the morphology of inkjet printed tracks has been proposed by printing the ink into the structured channels with predefined topography. Silver nanowires were synthesised and dispersed in methanol with help of copolymer F127. They were subsequently deposited on plastic and glass substrates forming conductive and transparent films.
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    Synthesis of silver nano particles and fabrication of aqueous Ag inks for inkjet printing
    (Elsevier Science B.V., Amsterdam., 2011-10-03T00:00:00Z) Kosmala, A.; Wright, Robert V.; Zhang, Qi; Kirby, Paul B.
    The main problem in preparing stable and printable inks containing nanoparticles for inkjetprinting is to overcome the strong agglomeration of the particles in dispersion medium. In thisstudy, the silver particles with diameter around 50 nm were produced by a simple wet chemistrymethod. Stable aqueous printable inks were formulated by using the combination of a triblockcopolymer and high intensity focused ultrasound (HIFU). Various factors that affect the inkstability, such as, copolymer content and time of HIFU treatment, were investigated. The inkcontaining 5 wt% silver has a viscosity of about 2 mPas and surface tension 30 mN/m at 25◦C,which meet inkjet printer requirements. Such inks have been successfully printed on Al2O3ceramics and low-temperature co- fired ceramics (LTCC) and the printed films show lowresistivit