3 results on '"Haseeb Iqbal"'
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2. Sedimentation and stabilization of nano-fluids with dispersant
- Author
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Shahid Raza Malik, Muhammad Abdullah, Muhammad Munir Sajid, Yasir Javed, Syed Zajif Hussain, Muhammad Haseeb Iqbal, Wasif Razzaq, and Naveed Akhtar Shad
- Subjects
Poly(methacrylic acid) ,Materials science ,020209 energy ,Nanoparticle ,02 engineering and technology ,Sedimentation ,021001 nanoscience & nanotechnology ,Dispersant ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Nanofluid ,Isoelectric point ,chemistry ,Chemical engineering ,0202 electrical engineering, electronic engineering, information engineering ,Zeta potential ,0210 nano-technology ,Dispersion (chemistry) - Abstract
Stability of nanofluids is one of the major parameters which measures its effectiveness. The agglomeration of nanoparticles reduces the stability of nanofluids and consequently affects their technologically relevant properties. In this study, stability of alumina nanoparticles (size ∼ 50 nm) in ethanol-water mixture with and without dispersant has been investigated. Sodium salt of poly methacrylic acid (SPMAA) as a dispersant were used in this investigation. Clear solution height with respect to time, sedimentary photographs and zeta potential techniques have been used to analyze the stability behavior of nano-fluid. The effect of binary mixture proportions and dispersion’s pH has been investigated and discussed. The results showed that sedimentation, zeta potential and photographic techniques have a great correspondence with each other. SPMAA has been used as the dispersant in low concentration (0.03 ml) and has a negative impact on the stability of nano-fluids. The isoelectric point of alumina found to be at pH 7 but with dispersant shifted towards acidic region (pH 4.5). Higher binary mixture concentrations (10% and 90%) by weight exhibited good stability.
- Published
- 2018
- Full Text
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3. Unexpected aqueous UCST behavior of a cationic comb polymer with pentaarginine side chains
- Author
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Nicolas Zydziak, Delphine Chan-Seng, Mélanie Legros, Antoine Combes, Philippe Lavalle, Emeric Wasielewski, Fouzia Boulmedais, Alain Chaumont, Loïc Jierry, Muhammad Haseeb Iqbal, Institut Charles Sadron (ICS), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Chimie de la matière complexe (CMC), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'innovation moléculaire et applications (LIMA), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Biomatériaux et Bioingénierie (BB), Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Matériaux et nanosciences d'Alsace (FMNGE), and Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Materials science ,Polymers and Plastics ,General Physics and Astronomy ,arginine ,02 engineering and technology ,010402 general chemistry ,Methacrylate ,01 natural sciences ,Hydrophobic effect ,Coulomb-defying interaction ,Upper critical solution temperature ,Materials Chemistry ,[CHIM]Chemical Sciences ,Thermoresponsive polymers in chromatography ,guanidinium self-association ,chemistry.chemical_classification ,Organic Chemistry ,Cationic polymerization ,Chain transfer ,Polymer ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,chemistry ,Chemical engineering ,Polymerization ,Thermoresponsive polymer ,upper critical solution temperature ,0210 nano-technology ,Chimie/Polymères - Abstract
International audience; Thermoresponsive polymers, undergoing a reversible chemical or physical change using temperature as stimulus, attract increasing interest in particular as adaptable biomaterials. Except for zwitterionic polymers, fully charged polymers require the presence of specific ions to exhibit an upper critical solution temperature (UCST) in water. Herein, we report the discovery of an UCST in pure water for fully cationic comb polymers based on oligoarginine pendent grafts. These polymers were prepared using an original strategy based on solid-phase peptide synthesis of pentaarginine methacrylate-based macromonomer and its polymerization through reversible addition-fragmentation chain transfer. Despite their cationic nature, guanidinium groups from the arginine have the ability to self-associate at low temperature through hydrophobic interactions into stacked pair configuration defying the expected Coulomb interactions. These results pave the way to biomedical applications such as antimicrobial materials and drug delivery systems through the tuning of the polymer structure.
- Published
- 2020
- Full Text
- View/download PDF
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