Structural analysis of paper substrate for flexible microfluidics device application.

Purpose: The purpose of this paper is to predict a suitable paper substrate which has high capillary pressure with the tendency of subsequent fluid wrenching in onward direction for the fabrication of microfluidics device application. Design/methodology/approach: The experiment has been done on the Whatman^TM grade 1, Whatman^TM chromatography and nitrocellulose paper samples which are made by GE Healthcare Life Sciences. The structural characterization of paper samples for surface properties has been done by scanning electron microscope and ImageJ software. Identification of functional groups on the surface of samples has been done by Fourier transform infrared analysis. A finite elemental analysis has also been performed by using the "Multiphase Flow in Porous Media" module of the COMSOL Multiphysics tool which combines Darcy's law and Phase Transport in Porous Media interface. Findings: Experimentally, it has been concluded that the paper substrate for flexible microfluidic device application must have large number of internal (intra- and interfiber) pores with fewer void spaces (external pores) that have high capillary pressure to propel the fluid in onward direction with narrow paper fiber channel. Originality/value: Surface structure has a dynamic impact in paper substrate utilization in multiple applications such as paper manufacturing, printing process and microfluidics applications. [ABSTRACT FROM AUTHOR]