![]() ![]() #ALEXANDROS CHREMOS SERIES#These findings are also closely related to relative simple case of electrolyte solutions, where the strength of solvent interaction with ionic species dictates the location of the ion along the Hofmeister series and modulating the solution properties of these solutions such as viscosity, density, and surface tension. View public records and comprehensive background report on Alexandros Chremos in Newark DE including phones, emails, current and past addresses, relatives, criminal and civil records, social media, education, employment, and more. Our findings demonstrate that the solvent is responsible for heterogeneous structure formation in salt-free polyelectrolyte solutions, revealing the essential role of the solvent interactions with the charged species in the description of the polyelectrolyte solutions. To probe this effect, we perform molecular dynamics simulations based on a coarse-grained model of polyelectrolyte solutions with an explicit solvent. This effect has significant implications for the function of proteins and other natural occurring polyelectrolytes (e.g., DNA), as emphasized long ago by Kirkwood and coworkers. The theoretical difficulties are especially great for flexible polyelectrolytes due to the additional complex coupling between the polyelectrolyte chain configurations and a diffuse 'polarizable' cloud of counter-ions around these polymers. While, it is widely appreciated that highly charged particles having the same charge to form dynamic clusters in solution, an accepted theoretical framework which accounts for this ubiquitous phenomenon, has been slow to develop. This behavior, exhibited by star-shaped polystyrenes with functionality f8 arms and molecular weights per arm M arm < M e ( M e is. Most polymers encountered in living systems are polyelectrolytes because of their solubility in water, and this broad class of polymers is also ubiquitous in commercial materials in which water solubility is required examples include hydrogels in diapers and gene delivery, thickeners in food industries, drug delivery, water purification agents, and cosmetics. E-mail:, Abstract We explore the monovalent counter-ion distribution around flexible highly-charged polyelectrolytes with different molecular architectures (linear chains, stars, and unknotted and trefoil rings) using molecular dynamics simulations that include an explicit solvent that interacts. The surface relaxation dynamics of supported star-shaped polymer thin films are shown to be slower than the bulk, persisting up to temperatures at least 50 K above the bulk glass transition temperature T bulk g. Title: Solvation effects in (poly)electrolyte solutions The diffusivity of the long chain nanoparticles exhibits a minimum at an intermediate temperature and volume fraction where the polymer brushes of neighboring particles overlap, but must stretch to fill the interparticle space.ChBE Seminar Series: Alexandros Chremos, NISTĪmy Alexandros Chremos, Postdoctoral Researcher at NIST Nanoparticles with longer chains exhibit a more gradual increase in the structural relaxation time with decreasing temperature and concomitantly increasing particle volume fraction. Alexandros Chremos Disordered hyperuniform materials are exotic amorphous systems that simultaneously exhibit anomalous suppression of long-range density fluctuations, comparable in amplitude to. Solvent-free nanoparticles with short chains undergo a glass transition as indicated by a vanishing diffusivity, diverging structural relaxation time and the formation of body-centered-cubic-like order. Whereas longer chains lead to a larger hydrodynamic radius and lower relative diffusivity for grafted particles in a melt, bulk solvent-free nanoparticles with longer chains have higher relative diffusivities than their short chain counterparts. Solvent-free, polymer-grafted nanoparticles as well as grafted nanoparticles in a melt were compared to a reference system of bare (ungrafted) particles in a melt. The diffusivity and structural relaxation characteristics of oligomer-grafted nanoparticles have been investigated with simulations of a previously proposed coarse-grained model at atmospheric pressure. ![]()
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