Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 19 of 19 for “"semi-dilute"”.
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Single polymer dynamics in semi-dilute solutions: linear and ring polymers
… of single molecule studies has focused on dilute solutions of linear polymers. In this thesis, we effectively extend single molecule imaging to increasingly complex polymeric systems of increasing polymer concentration and more complex chain architectures. In this way, we aim to address …
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The orientation state of semi-dilute rigid fibre suspensions in a linearly contracting channel
… interactions on the orientation state of a semi-dilute, rigid fibre suspension flowing through a linear contracting channel under laminar flow conditions. The effects of fibre-fibre interactions are modeled mathematically, the governing equations solved numerically and the predicted results …
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Steady spinning of synthetic silk-like fibers and transient filament stretching of semi-dilute and concentrated polymeric fluids
Thesis: S.M., Massachusetts Institute of Technology, Department of Chemical Engineering, 2001
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Single molecule studies of branched polymer dynamics in non-dilute solutions
… the dynamics of linear and ring polymers in dilute and non-dilute solutions, and well-defined comb polymers in ultra-dilute solutions (Chapter 1). However, single molecule studies have not yet been extended to non-dilute solutions of branched polymers. In this Ph.D. dissertation, I report the …
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The rheo-optics of shear thickening and structure formation in polymer solutions
… carried out in decalin and bromobenzene in the semi-dilute region using a couette device capable of shear rates up to 8,000 s$\sp{-1}.$
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Solution Properties of Polymer Nanostructures Studied by Scattering Techniques
… brushes and spherical microgels are studied at dilute and semi dilute concentration regime by using scattering techniques. The structure of the cylindrical polymer brushes and understanding the conformational changes of the flexible cylinders with the concentration was especially studied by …
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ΕΙΣΑΓΩΓΗ ΚΑΙ ΜΕΛΕΤΗ ΜΙΑΣ ΝΕΑΣ ΚΡΙΣΙΜΗΣ ΣΥΓΚΕΝΤΡΩΣΗΣ ΣΤΗ ΠΕΡΙΟΧΗ ΤΩΝ ΑΡΑΙΩΝ ΜΑΚΡΟΜΟΡΙΑΚΩΝ ΔΙΑΛΥΜΑΤΩΝ
… NEW CRITICAL CONCETRATION C** WHICH SEPERATE THE DILUTE SOLUTIONS IN TOW REGIMES. THE REGIME OF VERY DILUTE SOLUTIONS C C<C** AND THE REGIME OF DILUTE SOLUTION (C>C**). IT IS PROPOSED A MODEL WHICH DESCRIBE THIS CRITICAL CONCENTRATION. THE INFLUENCES IN THIS CRITICAL CONCENTRATION OF THE SOLVENT, …
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Soft hydrated sliding interfaces as complex fluids
… behavior due to its rheological similarity to a semi-dilute polymer solution. In this work we map 3 lubricating regimes between a polyacrylamide surface and an aluminum annulus using stepped-velocity tribo-rheometry over 5 decades of sliding speed in increasing and decreasing steps. We postulate …
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Equilibrium and dynamics of ionic solutions
… and consistent theory but it is valid only in dilute media because it is insufficient on two points: it considers ions as infinitesimally small and ignores their correlations. Consequently a new theory of small ions is developed in which ions are treated as hard spheres and their correlations …
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Responsive polymers for dynamic modulation of bio-macromolecular transport properties
… and welldefined boundaries between the dilute and semi-dilute regimes. The copolymers are strongly surface active, an uncommon observation for random copolymers, and exhibit pronounced photoviscosity effects at higher concentrations. Trans-to-cis isomerization under UV light leads to …
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Fabrication and light scattering study of multi-responsive nanostructured hydrogels and water-soluble polymers.
… interpenetrates into the PNIPAM network. The semi-dilute aqueous solutions of the PNIPAM-PAAc IPN microgels exhibit an inverse thermo-reversible gelation. Furthermore, IPN microgels undergo the reversible volume phase transitions in response to both pH and temperature changes associated to …
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Synthesis and supramolecular assembly of biomimetic polymers
… a wealth of information on linear flexible and semi-flexible polymers in dilute solutions. However, few investigations have focused on industrially relevant complex topologies (e.g., star, comb, hyperbranched polymers) in industrially relevant solution conditions (e.g., semi-dilute, …
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Improved models of colloidal gels : kinetic arrest relaxation dynamics, structural breakdown and the role of hydrodynamic interactions
… analysis is used to study the rheology of semi-dilute, attractive colloidal dispersions and it is demonstrated that both hydrodynamic interactions and the interparticle potential critically affect the viscoelasticity of the material. A normal mode analysis on colloidal gels is conducted …
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Structure, Dynamics and Rheology of Polymer Solutions from Coarse-Grained Molecular Dynamics: Effects of Polymer Concentration, Solvent Quality and Geometric Confinement
… viscosity and polymer</p> <p>concentration in dilute and semi-dilute regimes are presented and compared to</p> <p>experiment results. Shear thinning behavior is observed in both dilute and semidilute</p> <p>solutions in non-equilibrium molecular dynamics simulations. Possible approaches to</p> …
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Modelling of colloidal dynamics in complex soft matter systems
… previous results for hard-spheres fluids under semi-dilute conditions. The new framework has also unveiled a new rich physical behavior by studying the microstructure of two paradigmatic cases of physically relevant interactions, the attractive Lennard-Jones potential and the Debye-Hückel or …
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New Applications of Fluorescence Correlation Spectroscopy in Materials Science
… capable of determining the crossover between the dilute and the semi-dilute concentration regime. Dye-labelled polymer chains were mixed with unlabelled polymer chains of the same length and their mobility was measured by FCS for different mixing ratios. The change of the mobilities leads to the …
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Single molecule studies of branched polymer dynamics
… such as simple shear flow or linear mixed flows, semi-dilute solutions, and concentrated solutions. These experiments will provide a molecular basis for phenomena observed in branched polymers, from viscosity modification of blended branched polymer solutions to hierarchical relaxation mechanisms …
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Structure, Dynamics and Association of Thermosensitive Core-Shell Particles
… local structure of colloidal latex particles in dilute suspension at room temperature by cryo-TEM. The density profile derived from the cryo-TEM micrographs by image processing for the core and core-shell particles was compared to the results obtained by SAXS. Full agreement was found for the …
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Electrohydrodynamic interactions of colloidal particles undergoing Quincke rotation
… to capture interactions between particles in semi-dilute or concentrated suspensions. In particular, experiments in suspensions typically exhibit weaker angular velocities than predicted by the theory for an isolated sphere. Also, the critical field above which rotation takes place has been …