Search for: amphiphilics
0.005 seconds

    The Impact of Temperature on Surface Activity and Stability of Surface Modified Nano Particles

    , M.Sc. Thesis Sharif University of Technology Masoudi, Ghasem (Author) ; Mohammadi, Ali Asghar (Supervisor)
    Surface modification is an important property of nano particles. In this project surface of silica nano particles modified with hydrophobic and hydrophilic groups to imrprove surface activity of nano particles. Purpose of this project is to study surface activity of surface modified silica nano particles in different temperatures from 20 to 70 degree centigrade. Also effect of salt and time on the surface activity is studied. At first nano particles modified just with haydrophobic groups and then just with hydrophilic groups (hydrophobic and hydrophilic nano particles) and after that, the surface modification done with both hyadrophilic and hydrophobic groups (amphiphilic nanoparticles).... 

    Synthesis of Amphiphilic Nanoparticles with Different Alkyl Chains and their Application in Enhanced Oil Recovery

    , M.Sc. Thesis Sharif University of Technology Rajabi, Vahid (Author) ; Mohammadi, Ali Asghar (Supervisor)
    Important features of the nanoparticles properties are their high superficial area and being able to reform their surface. In this study, the repairable property used to reform surface of silica nanoparticles (Those are used more frequently than other nanoparticles). Repairing of surface are doing to use nanoparticles as a surface-active material in enhanced oil recovery. Silane compounds with different chain length are used to create hydrophobic nanoparticles and PEG compounds are used to create hydrophilic nanoparticles. Also amphiphilic nanoparticles are created with a combination of both hydrophilic and hydrophobic compounds. To investigate the usefulness of nanofluids are made up of the... 

    Design of Smart Magnetic Micellar Nanocarrier Based on Modified Polycaprolactone for Targeting Delivery of Paclitaxel as Anticancer Drug

    , M.Sc. Thesis Sharif University of Technology Dastanpour, Lida (Author) ; Pourjavadi, Ali (Supervisor)
    Today, current methods are used for treatment of cancers. Patient experiences a period of hard treatment during destruction of both healthy and diseased cells. Researchers are following stimulus- response drug delivery systems that they control time and position of drug release. Meanwhile, micellar nanoparticles are important, because it can transport the hydrophobic anticancer drugs from body's physiological barriers. On the other hand, tumour tissue has low pH and high temperature as compared to health tissue. Therefore, using pH and thermosensitive polymer coating could be effective in triggered drug release. In the first study, micellar systems were synthesized which were responsive to... 

    Facile synthesis of cauliflower-like hydrophobically modified polyacrylamide nanospheres by aerosol-photopolymerization

    , Article European Polymer Journal ; Volume 83 , 2016 , Pages 323-336 ; 00143057 (ISSN) Shaban, M ; Ramazani, S. A. A ; Ahadian, M. M ; Tamsilian, Y ; Weber, A. P ; Sharif University of Technology
    Elsevier Ltd  2016
    Amphiphilic copolymers consist of hydrophilic and hydrophobic monomer units have attracted great technological attention recently, owing to their unique properties and their ability to stabilize various interfaces in aqueous systems. This paper presents a novel and facile approach to produce spherical polyacrylamide, polystyrene and hydrophobically modified polyacrylamide (HM-PAM), as one of the most important type of amphiphilic copolymers, using a continuous aerosol-photopolymerization for the first time. To this end, the monomer droplets were generated by an atomizer, then photopolymerization was initiated ‘‘in flight’’ by ultraviolet (UV) irradiation of the aerosol monomer droplets... 

    Inhibiting asphaltene precipitation from Iranian crude oil using various dispersants: Experimental investigation through viscometry and thermodynamic modelling

    , Article Fluid Phase Equilibria ; Volume 442 , 2017 , Pages 104-118 ; 03783812 (ISSN) Saeedi Dehaghani, A. H ; Badizad, M. H ; Sharif University of Technology
    Elsevier B.V  2017
    Asphaltene precipitation is a major assurance problem posing significant technical and economic loss on petroleum industry. To tackle this issue, various treatments have been proposed and applied by industry. Amongst, inhibiting or retarding the asphaltene precipitation has been understood as the most efficient approach. In this regard, blending crude oil with chemical additives could appreciably heighten its stability. Surfactants, owing to amphiphilic nature, could keep asphaltene dissolved in crude oil by precluding self-tendency of those particles to making agglomerates. Despite importance of this subject, there is still lack of sufficient experimental data to evaluate effectiveness of... 

    Nontoxic concentrations of PEGylated graphene nanoribbons for selective cancer cell imaging and photothermal therapy

    , Article Journal of Materials Chemistry ; Volume 22, Issue 38 , 2012 , Pages 20626-20633 ; 09599428 (ISSN) Akhavan, O ; Ghaderi, E ; Emamy, H ; Sharif University of Technology
    Reduced graphene oxide nanoribbons functionalized by amphiphilic polyethylene glycol (rGONR-PEG) were applied to attach arginine-glycine-aspartic acid (RGD)-based peptide and cyanine dye 3 (cy3) for targeting ανβ3 integrin receptors on human glioblastoma cell line U87MG and its selective fluorescence imaging, respectively. The rGONR-PEG suspension with a concentration of 100 μg mL -1 showed ∼14 and 2.4-fold higher near infrared (NIR) absorption at 808 nm than GONR (with dimensions of ∼80 nm × 1 μm) and rGO-PEG sheets (with lateral dimensions of ∼2 μm), respectively. The rGONR-PEG-cy3-RGD exhibited highly efficient NIR photothermal therapy performance (concentrations ≥1.0 μg mL-1 resulted in... 

    Use of surfactants in cellulose nanowhisker/epoxy nanocomposites: effect on filler dispersion and system properties

    , Article Cellulose ; Volume 22, Issue 5 , 2015 , Pages 3161-3176 ; 09690239 (ISSN) Emami, Z ; Meng, Q ; Pircheraghi, G ; Manas-Zloczower, I ; Sharif University of Technology
    Kluwer Academic Publishers  2015
    Cellulose nanowhiskers (CNWs) prepared via TEMPO mediated oxidation are used as biodegradable filler in an epoxy matrix. Since CNWs are hydrophilic and epoxy is hydrophobic, amphiphilic block copolymer surfactants are employed to improve the interactions between the filler and the matrix. The surfactants used are Pluronics, a family of triblock copolymers containing two poly(ethylene oxide) blocks and one poly(propylene oxide) block. In this study, Pluronic L61 and L121 with molecular weight of 2000 and 4400 g/mol and hydrophilic to lipophilic balance of 3 and 1 respectively, are used and their effect on the dispersion of CNWs in epoxy is discussed. The hydrophilic tails of Pluronics... 

    Thermo- and pH-sensitive dendrosomes as bi-phase drug delivery systems

    , Article Nanomedicine: Nanotechnology, Biology, and Medicine ; Volume 9, Issue 8 , 2013 , Pages 1203-1213 ; 15499634 (ISSN) Adeli, M ; Fard, A. K ; Abedi, F ; Chegeni, B. K ; Bani, F ; Sharif University of Technology
    Fully supramolecular dendrosomes (FSD) as bi-phase drug delivery systems are reported in this work. For preparation of FSD, amphiphilic linear-dendritic supramolecular systems (ALDSS) have been synthesized by host-guest interactions between hyperbranched polyglycerol having β-cyclodextrin core and bi-chain polycaprolactone (BPCL) with a fluorescine focal point. Self-assembly of ALDSS in aqueous solutions led to FSD. They were able to encapsulate paclitaxel with a high loading capacity. The dendrosome-based drug delivery systems were highly sensitive to pH and temperature. They were stable at 20-37. °C and pH7-8, but dissociated and released drug at temperatures lower than 20. °C or higher...