Surface Science

Surface Science

Biomolecule-Surface Interactions
Gözde İnce

In our group, we also design bio-active smart polymeric surfaces for immobilization and separation of proteins. Bio-active smart polymer surfaces are produced using initiated chemical vapor deposition (iCVD) technique, followed by functionalization of the surface with high performance immobilizer (ligands) and stimuli responsive polymers. Improving the mechanical properties of the polymer films, increasing the immobilization capacity of ligands and studying the surface-protein interactions for a better control of attachment and detachment of proteins are within the framework of this project.


Superhydrophobic Surfaces
Yusuf Menceloğlu

The Lotus Effect: Thanks to nature... Inspired by the ever clean, highly water repellent surfaces of Lotus (Nelumbo Nucifera) leaves, our team has been working on producing similar, superhydrophobic surfaces via electrospinning/spraying. Such biological or synthetic surfaces are unique with their microscopically rough topographies comprising micron, sub-micron and nanometer scale features, which allow very limited contact area at the liduid-solid interface when combined with non-polar outermost surface chemistry. Corresponding outcomes are remarkably high advancing water contact angles varying generally between 150 and 180o, and relatively low threshold water sliding angles as low as 0o, or pinned droplets (despite the high advancing contact angles) depending on the geometry of the surface topography. For achieving the desired final properties, both the chemistry and the topography of the surface must be engineered, as our team has been realizing via co-polymer synthesis and electrospinning/spraying, respectively.

Our approach to copolymer design is straightforward; the monomer that will dominate the polymer backbone is selected according to the desired bulk properties of the final coating, and polymerized with a relatively low amount of a non-polar component (e.g. a fluorinated monomer or a crosslinker) which will dominate the outermost surface for minimizing the surface free energy. The coating is then formed from the copolymer via electrospinning/spraying. One example is solvent resistive superhydrophobic surfaces of copolymers having reactive groups such as isocyanate or epoxy, which can be crosslinked during or after electrospinning/spraying. Another example is perfectly hydrophobic surfaces, having practically no interaction with water (180o contact angles and 0o threshold sliding angles) achieved via a combination of self-assembly and particular electrospraying process control to form a dual scale roughness profile. We also perform theoretical investigation of the formation of topographical features. More than a decade of applied research has provided our group a solid capability to tune the wettability profile of a polymer surface using electrospinning/spraying.

  • K Acatay, E Simsek, C Ow‐Yang, YZ Menceloglu. Tunable, superhydrophobically stable polymeric surfaces by electrospinning. Angewandte Chemie International Edition 43 (39), 5210-5213
  • E Simsek, K Acatay, YZ Menceloglu. Dual scale roughness driven perfectly hydrophobic surfaces prepared by electrospraying a polymer in good solvent–poor solvent systems. Langmuir 28 (40), 14192-14201
  • E Ozden-Yenigun, E Simsek, YZ Menceloglu, C Atilgan. Molecular basis for solvent dependent morphologies observed on electrosprayed surfaces. Physical Chemistry Chemical Physics 15 (41), 17862-17872