A Generalized Drop Length–Height Method for Determination of Contact Angle in Drop-on-Fiber Systems

Song, Bihai; Bismarck, Alexander; Tahhan, Ralf; Springer, Jürgen

doi:10.1006/jcis.1997.5218

Cited by 97 publications

(55 citation statements)

References 14 publications

(17 reference statements)

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“…In this work we observed exclusively the characteristic symmetrical droplet type in the absence of an applied electric field, as shown in Fig 2. When the diameter of the cylinder is less than the capillary length, l cap = ! "g ( ) 1/2 , the surface tension force dominates over the gravitational force, and the shape of the droplet is found by minimizing the surface free energy [32][33]. Following Carroll, we determine both the volume (V d ) and contact angle (θ) for a liquid on a wire from photographic measurements of the diameter of the droplet at its widest point (2h) and the length (l d ) of the droplet, by solving the following set of equations: [31] ( ) …”

Section: Droplet Shapementioning

confidence: 99%

Free surface electrospinning from a wire electrode

Forward

Rutledge

2012

Chemical Engineering Journal

143

110

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Electrostatic jetting from a free liquid surface offers an alternative to conventional electrospinning in which jets are emitted from spinnerets. In this work we analyze a system in which a wire electrode is swept (in a rotary motion) through a bath containing a polymeric solution in contact with a high voltage, resulting in entrainment of the fluid, the formation of liquid droplets on the wire and electrostatic jetting from each liquid droplet. Solutions of polyvinylpyrrolidone in ethanol were used as test systems to evaluate each stage of the process.The volume of individual droplets on the wire were measured by photographic methods and correlated with the viscosity, density and surface tension of the liquid, and with system parameters such as electrode rotation rate and wire diameter. The local electric field in the absence of liquid entrainment was modeled using conventional electrostatics, and jet initiation was found to occur consistently at the angular position where the electric field exceeds a critical value of 34 kV/cm, regardless of rotation rate. Two operating regimes were identified. The first is an entrainment-limited regime, in which all of the entrained liquid is jetted from the wire electrode. The second regime is field-limited, in which the residence time of the wire electrode in an electric field in excess of the critical value is too short to deplete the fluid on the wire. The productivity of the system was measured and compared to the theoretical values of liquid entrainment. As expected, highest productivity occurred at high applied potentials and high rotation rates.

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Section: Droplet Shapementioning

confidence: 99%

Free surface electrospinning from a wire electrode

Forward

Rutledge

2012

Chemical Engineering Journal

143

110

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“…The contact angle between polymer melt droplets on single carbon fibres was measured using the generalised length-height method [14]. Individual carbon fibres were attached to a metal frame.…”

Section: Wetting Behaviour Of Carbon Fibres By Polymer Meltsmentioning

confidence: 99%

“…A total of 50 droplets were imaged on at least three different fibres for each fibre/matrix combination to ensure statistically significant results. Droplet images were imported into a custom made program designed to extract the droplet profile and calculate the contact angle [14].…”

Section: Wetting Behaviour Of Carbon Fibres By Polymer Meltsmentioning

confidence: 99%

“…Methods such as contact angle and zeta ( ) potential measurements have been used to characterise the adhesion behaviour between solids. In addition, the specific interaction between the reinforcing fibre and matrix can be directly quantified by contact angles between polymer melt droplets and individual carbon fibres [14,15] and single fibre pullout tests [14,[16][17][18]. Commonly, adhesion is easily be quantified by measuring contact angles ( ) between a solid and a partial wetting liquid.…”

Section: Introductionmentioning

confidence: 99%

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Carbon fibre reinforced poly(vinylidene fluoride): Impact of matrix modification on fibre/polymer adhesion

Tran

Kalinka

et al. 2008

Composites Science and Technology

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“…The wettability of CNT-grafted fibres by PMMA was quantified directly using the dropon-fibre method [25,26]. Single fibres were glued to a metal washer using an epoxy adhesive (Adhesive weld, J-B Weld, Slough) and dipped into PMMA powder.…”

Section: Contact Angle Measurementsmentioning

confidence: 99%

Carbon nanotube grafted silica fibres: Characterising the interface at the single fibre level

Qian

Bismarck

Greenhalgh

et al. 2010

Composites Science and Technology

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101

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Model polymer composites containing carbon nanotube (CNT) grafted fibres provide a means to investigate the influence of nanostructures on interfacial properties. Wellaligned nanotubes, with controllable length, were grown on silica fibres by using the injection chemical vapour deposition method, leading to a significant increase of the fibre surface area. In single fibre tensile tests, this CNT growth reaction reduced the fibre strength, apparently due to catalyst etching; however, the fibre modulus increased significantly. Contact angle measurements, using the drop-on-fibre method, indicated an excellent wettability of the CNT-grafted fibres by poly(methyl methacrylate) (PMMA).PMMA model composites were fabricated and studied using the single fibre fragmentation tests. A dramatic improvement (up to 150%) of the apparent interfacial shear strength (IFSS) was obtained for the composites containing CNT-grafted fibres.The improvement of IFSS was also influenced by the length and morphology of the grafted CNTs.

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A Generalized Drop Length–Height Method for Determination of Contact Angle in Drop-on-Fiber Systems

Cited by 97 publications

References 14 publications

Free surface electrospinning from a wire electrode

Free surface electrospinning from a wire electrode

Carbon fibre reinforced poly(vinylidene fluoride): Impact of matrix modification on fibre/polymer adhesion

Carbon nanotube grafted silica fibres: Characterising the interface at the single fibre level

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