Wall slip of polydisperse linear polymers using double reptation

Measurements of light scattering have given much information about formation and properties of fibrin. These studies have determined mass-length ratio of linear polymers (protofibrils) and of fibers, kinetics of polymerization and of lateral association and volume-mass ratio of thick fibers. This ratio is 5 to 1. On the one hand, this high value suggests that the fiber contains channels that allow the diffusion of enzymes such as Factor XHIa and plasmin; on the other hand, the high value appears paradoxical for a stiff fiber made up of elongated units (fibrin monomers) arranged in parallel. Such a high fiber volume is a property of only a small set out of many high-symmetry models of fibrin, which may be constructed from overlapping three-domain monomers which are arranged into strands, are aligned nearly parallel to the fiber axis and make adequate longitudinal and lateral contacts. These models contain helical protofibrils related to each other by rotation axes parallel to the fiber axis. The protofibrils may contain 2, 3 or 4 monomers per helical turn and there are four possible symmetries. A large specific volume is achieved if the ends of each monomer are slightly displaced from the protofibril axis, either by a shift or by a tilt of the monomer. The fiber containing tilted monomers is more highly interconnected; the two ends of a tilted monomer form lateral contacts with different adjacent protofibrils, whereas the two ends of a non-tilted monomer contact the same adjacent protofibril(s).

Download Full-text

Mapping the “Extra Solvent Power, ESP” of Ionic Liquids for Monomers, Polymers and Globular Nanoparticles

10.26434/chemrxiv.5384293.v1 ◽

2017 ◽

Author(s):

Jose A. Pomposo

Keyword(s):

Ionic Liquid ◽

Ionic Liquids ◽

Linear Polymers ◽

Green Solvents ◽

Ionic Polymers ◽

First Time ◽

Solvent Power

Understanding the miscibility behavior of ionic liquid (IL) / monomer, IL / polymer and IL / nanoparticle mixtures is critical for the use of ILs as green solvents in polymerization processes, and to rationalize recent observations concerning the superior solubility of some proteins in ILs when compared to standard solvents. In this work, the most relevant results obtained in terms of a three-component Flory-Huggins theory concerning the “Extra Solvent Power, ESP” of ILs when compared to traditional non-ionic solvents for monomeric solutes (case I), linear polymers (case II) and globular nanoparticles (case III) are presented. Moreover, useful ESP maps are drawn for the first time for IL mixtures corresponding to case I, II and III. Finally, a potential pathway to improve the miscibility of non-ionic polymers in ILs is also proposed.

Download Full-text

Wall slip

Physics Subject Headings (PhySH) ◽

10.29172/703a9d8c-f20e-4b6c-8840-5d80a681c821 ◽

2018 ◽

Keyword(s):

Wall Slip

Download Full-text

Cyclic generation of wall slip at the exit of plane Couette flow

Journal of Rheology ◽

10.1122/1.1562154 ◽

2003 ◽

Vol 47 (3) ◽

pp. 737-757 ◽

Cited By ~ 8

Author(s):

Hiroshi Mizunuma ◽

Hideyuki Takagi

Keyword(s):

Couette Flow ◽

Wall Slip ◽

Plane Couette Flow

Download Full-text

Effect of wall-slip on natural convection in a square cavity

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1132/1/012040 ◽

2021 ◽

Vol 1132 (1) ◽

pp. 012040

Author(s):

Kartik Suresh ◽

C K Arjun ◽

Damu Murali ◽

S Ajith Kumar

Keyword(s):

Natural Convection ◽

Wall Slip ◽

Square Cavity

Download Full-text

Wall slip of complex fluids: Interfacial friction versus slip length

Physical Review Fluids ◽

10.1103/physrevfluids.3.062001 ◽

2018 ◽

Vol 3 (6) ◽

Cited By ~ 11

Author(s):

Benjamin Cross ◽

Chloé Barraud ◽

Cyril Picard ◽

Liliane Léger ◽

Frédéric Restagno ◽

...

Keyword(s):

Slip Length ◽

Complex Fluids ◽

Wall Slip ◽

Interfacial Friction

Download Full-text

Quantification of shear viscosity and wall slip velocity of highly concentrated suspensions with non-Newtonian matrices in pressure driven flows

Rheologica Acta ◽

10.1007/s00397-021-01281-5 ◽

2021 ◽

Author(s):

Patrick Wilms ◽

Jan Wieringa ◽

Theo Blijdenstein ◽

Kees van Malssen ◽

Reinhard Kohlus

Keyword(s):

Shear Stress ◽

Liquid Phase ◽

Shear Rate ◽

Shear Viscosity ◽

Slip Velocity ◽

Volume Fraction ◽

Solid Volume Fraction ◽

Wall Slip ◽

Flow Index ◽

Concentrated Suspensions

AbstractThe rheological characterization of concentrated suspensions is complicated by the heterogeneous nature of their flow. In this contribution, the shear viscosity and wall slip velocity are quantified for highly concentrated suspensions (solid volume fractions of 0.55–0.60, D4,3 ~ 5 µm). The shear viscosity was determined using a high-pressure capillary rheometer equipped with a 3D-printed die that has a grooved surface of the internal flow channel. The wall slip velocity was then calculated from the difference between the apparent shear rates through a rough and smooth die, at identical wall shear stress. The influence of liquid phase rheology on the wall slip velocity was investigated by using different thickeners, resulting in different degrees of shear rate dependency, i.e. the flow indices varied between 0.20 and 1.00. The wall slip velocity scaled with the flow index of the liquid phase at a solid volume fraction of 0.60 and showed increasingly large deviations with decreasing solid volume fraction. It is hypothesized that these deviations are related to shear-induced migration of solids and macromolecules due to the large shear stress and shear rate gradients.

Download Full-text

Moldability improvement in microinjection molding via film lamination

Polymers and Polymer Composites ◽

10.1177/0967391120986503 ◽

2021 ◽

pp. 096739112098650

Author(s):

Dah Hee Kim ◽

Young Seok Song

Keyword(s):

Heat Transfer ◽

Light Guide ◽

Wall Slip ◽

Skin Layer ◽

Pattern Transfer ◽

Plastic Plate ◽

Resin Infusion ◽

Microinjection Molding ◽

Insulation Effect ◽

Thin Plastic

The purpose of this study is to integrate a polymeric film onto a mold to impede thermal heat transfer during resin infusion. A thin plastic plate was fabricated by using microinjection molding. A polyimide (PI) film was laminated onto a mold in an effort to produce a thin light guide plate (LGP). The film could decelerate the solidification of molten polymer in the cavity of mold and enhance the wall slip of resin on the mold. The insulation effect was modeled numerically. The surface roughness and pattern transfer characteristics of the LGP were evaluated. It was found that the fluidity of the resin increased due to the decreased skin layer during mold filling. The results showed that the strategy proposed in this study could help decrease the thickness of LGP effectively when manufacturing the part via injection molding.

Download Full-text