Directional water transport on hierarchically textured superhydrophobic rice leaf, nepenthes alata, and polymer fiber array 

Fiber-based functional smart structures/surfaces

[ The realization of artificial surfaces with special anisotropic non-wetting capability is inspiring for the development of self-cleaning surfaces, droplet microfluidics, droplet micro-reactors for precise chemical and/or nanomaterial synthesis, and droplet transport at precise volumes.  ]

Recently, we introduced on-fiber microfluidics as a new platform for fabrication of disposable microfluidic devices. Thermal drawing is used to modify surface texture of fibers, for the first time, to achieve free-standing micro-channels on fibers. We obtain well-ordered, perfectly aligned micro-channels on polymer fibers as small as 200 µm in diameter and as long as tens of meters in length. Intrinsical advantages of fibers; flexibility, covering large areas, anisotropicity are exploited for a number of designs. We demonstrated spontenous capillary flow along three-dimensional fiber geometries, switch systems that allow precise control on fluid flow, and a proof of concept colorimetric protein assay.

Surface textured fibers offer high-throughput fabrication of complex open microfluidic channel geometries which is challenging to achieve using current photo-lithography based techniques. We designed and prepared several microfluidic systems on either planar or 3D surfaces to demonstrate outstanding capability of the fiber arrays in control of fluid flow in both vertical and lateral directions. We believe that, surface textured fibers are well suited for fabrication of flexible, robust, lightweight and affordable microfluidic devices which expand the role of microfluidics in a scope of fields including drug discovery, medical diagnostics and monitoring food and water quality.


(1) fiber-based micro-reactor for uniform nanoparticle synthesis,
(2) large-area smart textile for water collection and fashion design,
(3) fiber-based smart surfaces with integrated devices for sensing or/and energy harvesting,
(4) fiber-based bio-inspired hierarchically structured surfaces,
(5) Liquid transport phenomena along in-fiber or on-fiber microfluidic devices,
(6) Wearable fiber-based smart devices.

Research highlights:

On fiber microfluidics

Related projects:

-Polymer encapsulated very long metal/semiconductor/polymer nanowire and nanotube arrays and their applications
Funding Agency: TUBITAK (COST)
Funding Amount: 178,000 USD
Period: 2011-2013

-Multifunctional nanostructured coatings using organically modified silica colloids for photovoltaics and sensors
Funding Agency: TUBITAK (COST)
Funding Amount: 163,000 USD
Period: 2012-2014

Representative publications:

Surface textured polymer fibers for microfluidics
A. Yildirim, M. Yunusa, F. E. Ozturk, M. Kanik, and Mehmet Bayindir
Advanced Functional Materials, volume 24, page 4569 (2014)
[ Supporting Information ] [ Video 1 ] [ Video 2 ] [ Video 3 ] [ Selected as Frontispiece ]

Bio-inspired hierarchically structured polymer fibers for anisotropic non-wetting surfaces
M. Yunusa, F. E. Ozturk, A. Yildirim, U. Tuvshindorj, M. Kanik, and Mehmet Bayindir
ACS Applied Materials and Interfaces, Under Review (2016)


Selected pictures: