Experimental determination of interfacial slip between polyethylene and thermoplastic elastomers

Himmel, Tobias; Wagner, Manfred H.

doi:10.1122/1.4824136

Cited by 10 publications

(1 citation statement)

References 12 publications

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“…condition. [5][6][7][8] In particular, it is widely accepted that several types of complex fluids such as polymeric melts and solutions, [9][10][11][12] elastomers, 13 gels, 14 wormlike micelles, [15][16][17] foams, 18,19 emulsions, 20 and colloidal suspensions 21,22 slip over a solid substrate when the wall shear stress (or shear rate) exceeds a critical value. The wall slip has a paramount effect on the flow and deformation of these complex fluids.…”

Section: Introductionmentioning

confidence: 99%

Microscopic origin of wall slip during flow of an entangled DNA solution in microfluidics: Flow induced chain stretching versus chain desorption

Hemminger

Boukany

2017

Biomicrofluidics

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Despite the relevance and importance of slip, a fundamental understanding of the underlying molecular mechanisms of wall slip in polymer flow is still missing. In this work, we investigate the slip behavior of an entangled DNA solution at a molecular scale using a confocal microscope coupled to a microfluidic device. From microscopic measurement, we obtain both the velocity profile and conformation of polymeric chains by visualizing DNA molecules during flow on various surfaces (ranging from weak to strong interactions with DNA molecules). In channel flow at a low Weissenberg number (Wi = 0.14), we observe a parabolic flow for an APTES-treated glass (with strong interaction with DNA) in the absence of slip, while a significant amount of slip has been observed for a regular glass (with a weak interaction with DNA). At higher flow rates (Wi > 1.0), strong slip appears during flow on APTES-treated surfaces. In this case, only immobile DNA molecules are stretched on the surface and other bulk chains remain coiled. This observation suggests that the flow induced chain stretching at the interface is the main mechanism of slip during flow on strong surfaces. Conversely, for slip flow on surfaces with weak interactions (such as unmodified or acrylate-modified glasses), polymeric chains are desorbed from the surface and a thin layer of water is present near the surface, which induces an effective slip during flow. By imaging DNA conformations during both channel and shear flows on different surfaces, we elucidate that either chain desorption or flow-induced stretching of adsorbed chains occurs depending on the surface condition. In general, we expect that these new insights into the slip phenomenon will be useful for studying the biological flow involving single DNA molecule experiments in micro/nanofluidic devices.

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Section: Introductionmentioning

confidence: 99%

Microscopic origin of wall slip during flow of an entangled DNA solution in microfluidics: Flow induced chain stretching versus chain desorption

Hemminger

Boukany

2017

Biomicrofluidics

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Melt fracture and wall slip of thermoplastic vulcanizates

Ghahramani

Zhang

Iyer

et al. 2020

Polymer Engineering & Sci

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Thermoplastic vulcanizates (TPVs) are blends of polypropylene (PP) (thermoplastic phase) and ethylene propylene diene monomer (EPDM) rubber (rubber phase) in which a high content of rubber EPDM is cross‐linked and dispersed in a thermoplastic matrix (PP) in the presence of oil (lubricant) and filler. Depending on the molecular characteristics of the constituent polymers, the level of curing and the amount of cross‐linked rubber, their processing (extrusion) exhibits various difficulties such as melt fracture (extrudate distortions). In this study, a number of different TPVs with various characteristics, including the degree of curing and amount of cross‐linked rubber are examined in capillary extrusion at two different temperatures (190°C and 205°C) relevant to real processing. First, the effect of the temperature on the yield stress is investigated using rheological measurements. Consequently, the flow behavior of the TPVs in capillary flow is studied concluding that TPVs slip massively (nearly plug flow) due to the presence of lubricant and the vulcanized rubber phase. Although there is little slip observed in PP samples, EPDMs themselves exhibit severe slip and melt fracture. As a consequence, the TPV samples essentially follow the slip behavior of EPDMs. Finally, the melt fracture analysis of several TPVs has shown that with increase of temperature and amount of cross‐linked rubber, the severity of TPVs' surface defects increases accordingly.

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Mixed convection heat transfer of double immiscible fluids in functional gradient material preparation

Ding

Zheng

et al. 2018

International Journal of Heat and Mass Transfer

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Experimental determination of interfacial slip between polyethylene and thermoplastic elastomers

Cited by 10 publications

References 12 publications

Microscopic origin of wall slip during flow of an entangled DNA solution in microfluidics: Flow induced chain stretching versus chain desorption

Microscopic origin of wall slip during flow of an entangled DNA solution in microfluidics: Flow induced chain stretching versus chain desorption

Melt fracture and wall slip of thermoplastic vulcanizates

Mixed convection heat transfer of double immiscible fluids in functional gradient material preparation

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