Surface Science

Surface Science

Porous Materials
Yuda Yürüm

MOFs

Metal organic frameworks are organic-inorganic solids with infinite and uniform crystalline coordination networks which are formed of metal ion or metal ion clusters and an organic molecule. They are promising materials for their high surface area, highly porous structure and tunable porosity and they are therefore promising candidate materials for hydrogen adsorption and storage, catalysis, heavy metal removal, membrane technologies, selective gas separation, methane storage, drug delivery, biosensor and semiconductors.

In our group, we have mainly focused our research on increasing the surface area and porosity of our metal organic frameworks. We are trying to figure out the mechanism and relation that lies behind the process parameters and the surface area and porosity.The characterization studies of our metal organic frameworks are conducted by X-ray diffractometer (XRD), scanningelectronmicroscopy (SEM), Brunauer–Emmett–Teller (BET) methodandthermogravimetricanalysis (TGA). Below are our metal organic frameworks synthesized with different synthesis strategies.

We have figured out that by different synthesis strategies, we have obtained different surface areas, porosities and surface properties. Now we are trying to find out new application areas that will broaden the usage of these highly promising materials.

Yurduşen, A. Yürüm Y. (2016) Investigation of the surface properties and potential application areas of novel copper based metal organic framework synthesized by solvothermal and microwave assisted method with different heating and drying temperatures and durations, washing and filtration procedure. Available at: https://presentations.acs.org/common/presentation-detail.aspx/Spring2016/INOR/INOR013c/2393626 (Accessed 22 November 2016)
Publications

Activated Carbon

The purpose of the present work is to manufacture a novel material based on activated carbon decorated with nanoparticles, and utilization of this material in the water purification.

Publications

Mesoporous Silica and Zeolite

Among mesoporous materials, FSM-16 is a good candidate because of its large and hexagonal pore structure with high specificsurface area. Indeed, the ordered structure of FSM-16 ensures the good dispersion of metalparticles. When FSM-16 is loaded with metal particles, it can be used as a catalyst forvarious applications such as CNT production, hydrogen storage and adsorption.


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.

Publications

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.

Publications
  • 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