Research Project: Buzlanmayı Engelleyen Polimer Kompozitler
Loading...
Contributors
Funders
ID
TB.00356
Authors
Demirel, Adem Levent
Faculty Member
Publications
Low ice adhesion anti-icing coatings based on PEG release from mesoporous silica particle loaded SBS
(Royal Society of Chemistry (RSC), 2022) Demirel, Adem Levent; Ijaz, Aatif; Miko, Annamaria; Department of Chemistry; Yes; College of Sciences
Release-based extremely low ice adhesion strength and durable anti-icing coatings were designed and realized by loading mesoporous silica particles (MSP) into the SBS polymer matrix and filling poly(ethylene glycol) (PEG) as the anti-icing agent into MSP/SBS composites. This approach allows the formation of a thin lubricating liquid layer of PEG and water at the ice/composite interface at sub-zero temperatures and results in ice adhesion strength as low as 3 kPa. The high specific surface area of MSP (428 m(2) g(-1)) as the anti-icing agent carrier significantly contributed to the retainment of PEG in the composites. The freezing time of water droplets on the composites increased and the ice adhesion strength decreased with the amount of PEG retained in the composites. After 15 icing/deicing cycles, the ice adhesion strength was measured to be similar to 5 kPa indicating a rather slow release (and removal with ice) of PEG at -10 degrees C from surface-exposed pores of MSP. The importance of PEG at the ice/composite interface was confirmed by ice adhesion strength measurements of frozen PEG-containing aqueous solutions on unfilled MSP/SBS composites. These results clearly show that PEG filled MSP/SBS composites demonstrate a passive anti-icing mechanism based on sustained release of PEG with extremely low ice adhesion strength and significant potential for longer-term use in sub-zero temperature and harsh environments.
Formation of mesoporous silica particles with hierarchical morphology
(Elsevier, 2020) Demirel, Adem Levent; Ijaz, Aatif; Miko, Annamaria; Yağcı, Mustafa Barış; Ow-Yang, Cleva W.; Department of Chemistry; KUYTAM (Koç University Surface Science and Technology Center); Yes; College of Sciences; Research Center
The transformation of mesoporous silica morphology from monoliths to spherical particles was investigated at room temperature in Pluronic F127/TEOS system as a function of HCl acid catalyst concentration to understand and control the mechanism. It is shown that the specific surface area and the size of mesoporous spherical silica particles can simply be adjusted by the catalyst concentration without using any additives or post-treatment. Above 3 M acid concentration, novel monodisperse micron sized spherical silica with hierarchical order of two levels was obtained. These silica spheres were formed of densely packed distorted hexagonal platelets of 20-30 nm in diameter. Within these platelets mesoporous channels were oriented along a single direction, however the platelets were randomly oriented in the spherical particles. Controlling the agglomeration of mesoporous silica primary particles by the concentration of the acid catalyst to obtain micron-sized spherical particles is novel. This approach allows the synthesis of particles whose sizes can be controlled in the range of similar to 1-4 mu m and specific surface area in the range of similar to 200-500 m(2)/g. The morphology of the particles transforms from spherical shape to mesoporous monoliths at acid concentrations below 1 M due to slow hydrolysis and condensation. These results are important in understanding the role of catalyst concentration on the formation mechanism of different morphologies of mesoporous silica.
