Wetting and transport properties of nanofibrous materials (Kornev)

Recently, nanofibers have attracted great attention as promising materials for building different constructs and nanodevices. These materials remain within the main stream of nanotechnology research and applications.  Nanofibers can be made porous or hollow and can be bundled and twisted into yarns. Because of their flexibility and porosity, and high surface area, nanofibrous constructs show great potential for filtration, separation, and probing/absorption of different fluids. The wetting and permeation properties are essential characteristics of these materials. The materials wettability depends on the surface energy of the material. For macroscopic materials, the surface energy is evaluated by analyzing the contact angles formed by droplets of different liquids. The permeation properties of non-deformable porous materials are determined by evaluating the flow rates of the testing fluid at different pressure differentials. The ratio of the flow rate to the pressure differential per unit length of the sample is called permeability. This parameter characterizes the permeation properties of the given porous solid. Precision control of wetting and permeation properties, however, is critical for the applications of the nanofibrous materials as micro- and nanofluidic conduits. One of the most challenging problem in characterization of nanofibrous constructs is that these materials are highly deformable and even a microdroplet can easily deform the material. The proposed research project will introduce an undergraduate student into an exciting area of nanotechnology where physics, chemistry, and materials science meet.

The student will be working in a team of graduate students and Post Doctoral associates and will help develop new experimental protocols for characterization of wetting and transport properties of nanofibrous materials. These materials will be produced by the student using advanced electrospining technology developed in Kornev’s group that allows one to collect nanofibers into yarns and apply different twist. The materials with precisely controlled porosity and nanofiber anisotropy will be then characterized using recently developed protocols for permeability and contact angle measurements with surface tensiometer Cahn DC. Nanofiber yarns will be functionalized using different silanes providing a variety of contact angles. After complete characterization of the synthesized nanofiber yarns, the student will study dynamic absorption of aerosol droplets by these yarns using a high speed video microscopy. The student will be trained in high speed imaging and data collection and archiving. We will introduce the basic image analysis techniques based on Matlab. Labview, and COMSOL Multiphysics software. The student will be trained to write technical reports. Assuming complete devotion to the project, the student can end up with a co-authorship of a peer-reviewed publication as happened with our former REU student, Bethany Kauffmann.

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