We continue to develop two-particle interfacial microrheology and have applied the technique to study the interfacial viscoelastic properties of immiscible poly(dimethylsiloxane) (PDMS)-poly(ethylene glycol) (PEG) interfaces. The interfacial storage and loss moduli are measured over a wide frequency range: at low frequencies, the interfaces are dominated by viscous responses whereas elasticity dominates at high frequencies. The zero-shear interfacial viscosity, estimated following the Cox-Merz rule and Cross model, falls between the bulk viscosities of the two individual polymers. Surprisingly, the interfacial relaxation time, calculated from the crossover of the storage and loss moduli, is observed to be an order of magnitude larger than that of the PDMS bulk polymers. The effects of tracer particle surface chemistry and size have also been investigated and show minimum influences on two-particle interfacial microrheology.
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http://dx.doi.org/10.1021/la102171k | DOI Listing |
Macromol Rapid Commun
March 2024
Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
This study investigates the effect of adding oligomers on the rheological properties of polymer nanocomposite melts with the goal of enhancing the processability of nanocomposites. The scaling analysis of plateau modulus (G ) is used in understanding the complex mechanical behavior of entangled poly(methyl acrylate) (PMA) melts upon oligomer addition. Increasing the oligomer amount led to a decrease in G and an apparent degree of entanglement (Z) in the neat polymer melt.
View Article and Find Full Text PDFPhys Rev E
July 2021
Department of Physics, PUC-Rio, Rio de Janeiro, 22453-900 RJ, Brazil.
We consider a system consisting of two interacting classical particles, each one subject to an on-site potential and to a Langevin thermal bath. We analytically calculate the heat current that can be established through the system when the bath temperatures are different, for weak nonlinear forces. We explore the conditions under which the diode effect emerges when inverting the temperature difference.
View Article and Find Full Text PDFPhys Rev E
June 2018
Center for Soft Matter and Biological Physics, Department of Physics, Virginia Polytechnic Institute & State University, Blacksburg, Virginia 24061, USA.
In the Widom-Rowlinson lattice gas, two particle species (A, B) diffuse freely via particle-hole exchange, subject to both on-site exclusion and prohibition of A-B nearest-neighbor pairs. As an athermal system, the overall densities are the only control parameters. As the densities increase, an entropically driven phase transition occurs, leading to ordered states with A- and B-rich domains separated by hole-rich interfaces.
View Article and Find Full Text PDFAAPS PharmSciTech
April 2017
Biotherapeutics Pharmaceutical Sciences, Pfizer, 700 Chesterfield Parkway West, Chesterfield, Missouri, 63017, USA.
The time-course and extent of visible particle (VP) and sub-visible particle (SVP) formation was monitored as a function of interfacial area (IA) for a model bioconjugate. To facilitate particle formation, the bioconjugate was agitated in a glass vial and exposed to IAs up to 478 mm. Since vials had equal fill and headspace volumes, the area of the air-water interface was varied by placing vials on angled blocks at 0°, 30°, 60°, or 90° from the horizontal.
View Article and Find Full Text PDFJ Chem Phys
January 2014
Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA.
Using molecular-dynamics simulation and Gibbs-Cahn Integration, we calculate the interfacial free energy γ of a binary hard-sphere fluid mixture at a structureless, planar hard wall. The calculation is performed as a function of packing fraction (density) for several values of the diameter ratio α = σ2∕σ1, where σ1 and σ2 are the diameters of the two particle types in the mixture. Our results are compared to those obtained from the bulk version of the White Bear Mark II (WBII) classical density-functional theory, which is a modification of the Fundamental-Measure Theory of Rosenfeld.
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