Patterned superhydrophobic paper for microfluidic devices obtained by writing and printing

Abstract

This work outlines inexpensive patterning methodologies to create open-air microfluidic paperbased devices. A phase-separation methodology was used to obtain biomimetic superhydrophobic paper, hierarchically composed by micro and nano topographies. Writing and printing are simple actions that can be used to pattern flat superhydrophobic paper with more wettable channels. In particular, inkjet printing permits controlling the wettability of the surface by changing the darkness of the printed regions. The difference between capillary forces provides the possibility to control and drive liquid flows through the open path lines, just by titling the piece of paper. Additionally, maintaining a continuous flow, it is possible to direct the liquid at different volumetric rates in a horizontal position along non-linear channel paths printed/written over the surface.

Dry, hydrophobic microfibrillated cellulose powder obtained in a simple procedure using alkyl ketene dimer

“…The hydrophobization effect demonstrated here is in good agreement with-or even surpasses the values of earlier studies (Jonoobi et al 2009;Missoum et al 2013). The highest value of 140°for MFC 4.0 AKD even attains almost superhydrophobic character, which begins at a water-contact angle of 150° (Sousa and Mano 2013). As suggested by Song and Yang (Song et al 2012;Yang et al 2014) the greatly increased hydrophobicity of AKD-modified MFC may be due to the introduction of long alkyl chains of AKD on the cellulose surfaces via ketoester linkages (Fig.…”

Paper‐Based Inkjet‐Printed Microfluidic Analytical Devices

“…Recently, several printing techniques have been adapted for this purpose, such as screen printing, [76,85] flexographic printing, [79,83] and digital printing. [7,70,72,74,77,78,80,81,84] Digital printing enjoys great popularity and wide use, since it can directly relay image information from a computer onto the print substrate, without the costly and time-consuming conversion of electronic data into printing plates, masks, or screens. Image transfer from the printer onto the surface of the paper substrate is achieved by digitally controlled direct deposition of ink.…”

Facile fabrication of superhydrophobic surfaces with corrosion resistance by nanocomposite coating of TiO2 and polydimethylsiloxane

“…Superhydrophobic surfaces with a water contact angle (CA) higher than 150 and a sliding angle (SA) less than 10 have attracted tremendous attention in scientific research as well as industrial field, such as self-cleaning [1], anti-corrosion [2], anti-bacterial [3], and microfluidic devices [4]. To create superhydrophobic surface, it is necessary to possess a low surface energy and high surface roughness [5,6].…”