Chemical Engineering / Kimya Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/14
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Conference Object Citation - Scopus: 4Effects of Surface Functional Groups on the Aggregation Stability of Magnetite Nanoparticles in Biological Media Containing Serum(Institute of Electrical and Electronics Engineers Inc., 2011) Wiogo, Hilda T. R.; Lim, May; Bulmuş, Volga; Amal, RoseSize stability of magnetite nanoparticles (MNP) with different surface functional groups in biological media was achieved by the addition of fetal bovine serum (FBS). The stability of the particles was attributed to the formation of protein coronas around the particles, which provides sufficient steric hindrance to prevent aggregation of the particles. The stability of different modified MNP were also studied in biological media containing bovine serum albumin (BSA) to further understand the stabilization mechanism. BSA was found to stabilize polyethyleneimine (PEI) modified MNP and polymethacrylic acid (PMAA) coated MNP, but not the bare MNP. These results indicate a difference in interactions between serum protein and the MNP that is govern by the type of functional groups on the MNP surface, with positively charged surface groups resulting higher protein adsorption and better stability. © 2011 IEEE.Conference Object Effect of Peo/Ppo Type Triblock Copolymers on Dispersion Behaviour of Aqueous Alumina Suspensions(Trans Tech Publications, 2001) Şakar, Aylin M.; Polat, Hürriyet; Çiftçioğlu, MuhsinThe aim of this study was to investigate the stability and dispersion behaviour of aqueous alumina suspensions in the presence of polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO/PPO/PEO) type block copolymers. The influence of water soluble triblock copolymers with molecular weight ranging from 2900 to 12600 g/mole were tested at Φ = 0.125, 1, 10, 20 vol % solid loading alumina suspensions by rheological, turbidity, sedimentation and surface tension measurements. The results indicate that an alternative dispersant for alumina suspensions is the PEO/PPO triblock copolymers. Their stabilisation mechanism was attributed to the depletion stabilisation. Rheological measurements indicated that these block copolymers (at high EO percentages) coupled with ultrasonic treatment have a positive effect on the dispersion of the agglomerated alumina suspensions. It was not possible to create stable dispersions in the absence of ultrasonic bath treatment. Turbidity measurements at Φ = 0.025, 0.125 vol % showed that, alumina suspensions with PEO/PPO added were stable and have higher turbidity values than block copolymer free suspensions.