Browsing by Author "Büke, G. C."

Now showing 1 - 2 of 2

Open Access
Assessment of silicon, glass, FR4, PDMS and PMMA as a chip material for acoustic particle/cell manipulation in microfluidics
(2023-03) Açıkgöz, Hande N.; Karaman, A.; Şahin, M. Akif; Çaylan, Ö. R.; Büke, G. C.; Yıldırım, E.; Eroğlu, İ. C.; Erson-Bensan, A. E.; Çetin, Barbaros; Özer, M. B.
In the present study, the capabilities of different chip materials for acoustic particle manipulation have been assessed with the same microfluidic device architecture, under the same actuator and flow conditions. Silicon, glass, epoxy with fiberglass filling (FR4), polydimethylsiloxane (PDMS) and polymethyl methacrylate (PMMA) are considered as chip materials. The acoustophoretic chips in this study were manufactured with four different fabrication methods: plasma etching, chemical etching, micromachining and molding. A novel chip material, FR4, has been employed as a microfluidic chip material in acoustophoretic particle manipulation for the first time in literature, which combines the ease of manufacturing of polymer materials with improved acoustic performance. The acoustic particle manipulation performance is evaluated through acoustophoretic focusing experiments with 2μm and 12μm polystyrene microspheres and cultured breast cancer cell line (MDA-MB-231). Unlike the common approach in the literature, the piezoelectric materials were actuated with partitioned cross-polarized electrodes which allowed effective actuation of different family of chip materials. Different from previous studies, this study evaluates the performance of each acoustophoretic device through the perspective of synchronization of electrical, vibrational and acoustical resonances, considers the thermal performance of the chip materials with their effects on cell viability as well as manufacturability and scalability of their fabrication methods. We believe our study is an essential work towards the commercialization of acoustophoretic devices since it brings a critical understanding of the effect of chip material on device performance as well as the cost of achieving that performance.
Open Access
Growth mechanism of 2D Mo2C on Cu via CVD
(American Chemical Society, 2023-7-7) Büke, G. C.; Caylan, Ömer Refet; Oğurtanı, Ö. T.
This study investigates the growth of Mo2C crystals via chemical vapor deposition (CVD) in the presence of a carbon (H2/CH4 gas)-containing environment. The study employs both theoretical and experimental approaches to investigate the vertical and lateral (in-plane) growth of Mo2C crystals. A physico-mathematical consideration is applied to develop an analytical forward model, which incorporates bulk diffusivities, surface diffusivities, and solubility gradients for Mo2C crystal growth. Coupled nonlinear flow equations have been advanced for the Mo-, Cu-, Mo2C layer framework and effectively predicted the Mo2C crystal growth rate for both vertical and lateral directions. Forming the Mo2C crystal height and diameter was directly correlated with copper layer thickness and time using the forward model and then validated by the experiments together with SEM and AFM studies. Studies showed that the Cu layer thickness plays a crucial role in controlling the height of the Mo2C crystal while it is not that critical in changing the lateral dimension of the crystal. Beyond simply enhancing Mo2C crystal growth and property-processing relationship, this study demonstrated the synthesis of designer Mo2C, which can be tailored to the needs of specific applications. This forward model will enable us to further enhance and exploit the family of analogs of materials previously demonstrated by other methods.