Усиление гидрофобных свойств структур ZnO золотым покрытием

The effect of enhancement the hydrophobic properties of the ensemble of micro- and nanostructures ZnO as a result of coating with gold was discovered. For the first time, it has been shown that coating the ensemble with a micro- and nanoparticle ZnO layer of gold leads to a sharp increase in the wetting edge angle from 145 to 168 ° (water drop volume 5 mm3) and a decrease in the hydrophobicity/hydrophilicity transition time under ultraviolet irradiation. Keywords: ZnO, gold, superhydrophobic.

Oscillatory Motion of Viscoelastic Drops on Slippery Lubricated Surfaces

The introduction of slippery lubricated surfaces allows the investigation of the flow of highly viscous solutions which otherwise will hardly move on standard solid surfaces. Here we present the study of the gravity induced motion of small viscoelastic drops deposited on inclined lubricated surfaces. The viscoelastic fluids exhibit shear thinning and, more importantly, a significant first normal stress difference N1. Despite the homogeneity of the surface and of the fluids, drops of sufficiently high N1 move down with an oscillating instantaneous speed whose frequency is found to be directly proportional to the average speed and inversely to the drop volume. The oscillatory motion is caused by the formation of a bulge at the drop rear that starts rolling around the moving drop.

Data-Driven Drop Formation Modeling in Nanoliter Drop-on-Demand Inkjet Printing

Drop formation models are essential for the control of drop-on-demand (DoD) inkjet printing process. Traditional numerical models are difficult to implement in real-time control. In this paper, an equivalent circuit model (ECM) is developed to motivate the implementation of a data-driven ARX model combined with a drop volume adjuster to estimate drop volume. Drop pinch-off instants and drop velocities are modeled in polynomials with respect to the parameters of the drive waveform. All models are validated through 10-fold cross validation. The simulation of the drop volume model shows good agreement with experimental results.

Influence of the Drop Volume and Applied Magnetic Field on the Wetting Features of Water-based Ferrofluids

In this work, the influence of the drop volume and applied magnetic field on the wetting features of water-based ferrofluids, is experimentally investigated. Firstly, water drops with volume in the range of 0.1–100 micro-liters are placed, by using micro-pipettes, on bare and coated acrylic plates, to gain reference data concerning the contact angle. Then, drops of water-based ferrofluid, with the volume ranging from 1 to 10 micro-liters, are set on bare acrylic plates, which are placed into the uniform magnetic field created, in normal direction to the plate, by using permanent magnets. Since the ferrofluid drops are elongated along the magnetic field, the contact angle increases at augmentation of the magnetic flux. Besides, when a critical magnetic flux is exceeded, ferrofluid drop loose contact with the plate and jumps towards the magnet. A heuristic equation to predict the fluctuation of the liquid surface tension versus the drop volume, and also versus the ratio of the applied magnetic field energy to the kinetic energy of the magnetic particles dispersed into the water-based ferrofluid, is suggested.

Drop Volume Control in Drop-on-Demand Inkjet Printing

Drop-on-demand (DoD) inkjet printing is used in precise-dosage deposition applications where consistent drop volume is important. Existing drop volume regulation in DoD inkjet printing are mainly open-loop approaches that are not effective in compensating for uncertainties during high volume printing applications. In this paper, a real-time image-based feedback system is proposed for regulating drop volume. A rotational symmetric model estimates drop volume from real-time images. Estimation accuracy is analyzed and validated. A simple feedback controller is developed to regulate drop volume. Experimental results validate the effectiveness of the proposed approach.