The role of interfacial viscoelasticity in the stabilization of an electrospun jet

Regev, Omri; Vandebril, Steven; Zussman, Eyal; Clasen, Christian

doi:10.1016/j.polymer.2010.03.061

Cited by 87 publications

(78 citation statements)

References 55 publications

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“…In this case, the extra stress contribution to the effective bulk properties originates from the stiff interfacial network formed by closepacked protein molecules. Indeed, solutions of bovine serum albumin, ovalbumins and other globular proteins 15,17,18,22 , acacia gum 25 , and monoclonal antibodies 24 are all examples of strong interfacial networks because their bulk rheological response measured on conventional torsional rheometers shows an apparent yield stress due to contribution of this adsorbed protein layer. While the quantitative decomposition of the interfacial and sub-phase contributions can be carried out using the additive model proposed by Sharma et al 20 , in practice, the interfacial contribution can be minimized by adding low molecular weight mobile surfactants to these protein solutions.…”

Section: Discussionmentioning

confidence: 99%

Interfacial viscoelasticity, yielding and creep ringing of globular protein–surfactant mixtures

2011

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Protein-surfactant mixtures arise in many industrial and biological systems, and indeed, blood itself is a mixture of serum albumins along with various other surface-active components. Bovine serum albumin (BSA) solutions, and globular proteins in general, exhibit an apparent yield stress in bulk rheological measurements at surprisingly low concentrations. By contrasting interfacial rheological measurements with corresponding interface-free data obtained using a microfluidic rheometer, we show that the apparent yield stress exhibited by these solutions arises from the presence of a viscoelastic layer formed due to the adsorption of protein molecules at the air-water interface. The coupling between instrument inertia and surface elasticity in a controlled stress device also results in a distinctive damped oscillatory strain response during creep experiments known as"creep ringing". We show that this response can be exploited to extract the interfacial storage and loss moduli of the protein interface. The interfacial creep response at small strains can be described by a simple second order system, such as the linear Jeffreys model, however the interfacial response rapidly becomes nonlinear beyond strains of order 1%. We use the two complementary techniques of interfacial rheometry and microfluidic rheometry to examine the systematic changes in the surface and bulk material functions for mixtures of a common non-ionic surfactant, Polysorbate 80, and BSA. It is observed that the nonlinear viscoelastic properties of the interface are significantly suppressed by the presence of even a relatively small amount of surfactant (c surf > 10 −3 wt.%).

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Section: Discussionmentioning

confidence: 99%

Interfacial viscoelasticity, yielding and creep ringing of globular protein–surfactant mixtures

2011

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“…Unfortunately, there is still no interfacial rheological method that would allow simultaneous determination of the interfacial shear properties and the actual dilatational characteristics at expansion rates on the order of 10 3 s -1 (expansion rates achieved at the beginning of the thin jet region-transition zone). Thus far, the best approximation involves interfacial shear measurements (61).…”

Section: The Role Of Interfacial Rheological Characteristics In the Ementioning

confidence: 99%

Interfacial rheology: An overview of measuring techniques and its role in dispersions and electrospinning

Pelipenko¹,

Kristl²,

Rošic³

et al. 2012

Acta Pharmaceutica

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Colloidal disperse systems represent the increasing number of modern delivery systems whose primary characteristic, a large interfacial area, causes thermodynamic instability. Therefore, the foremost challenge in dispersion design is the reduction of interface instability and an understanding of the behaviour of interfaces. Interfacial rheology is one of the most powerful tools for observing occurrences at the interphase. As previously mentioned, the stability of such systems is provided by the formation of a stable interfacial layer of surfactants around each dispersible particle. The stability of these systems can be improved by using more than one surfactant, but it must be kept in mind that different surfactants can have varying mechanisms of stabilisation, some of which can be mutually incompatible. Surfactant selection is therefore crucial and must be based on physicochemical properties, stability of the interfacial film, mobility of the molecules in the interfacial film, HLB, film formation kinetics, compatibility and interactions between molecules on the surface, CMC, etc. Interfacial rheological properties have yet to be thoroughly explored. Only recently, methods have been introduced that provide sufficient sensitivity to reliably determine viscoelastic interfacial properties. In general, interfacial rheology describes the relationship between the deformation of an interface and the stresses exerted on it.Due to the variety in deformations of the interfacial layer (shear and expansions or compressions), the field of interfacial rheology is divided into the subcategories of shear and dilatational rheology. While shear rheology is primarily linked to the long-term stability of dispersions, dilatational rheology provides information regarding short-term stability. Interfacial rheological characteristics become relevant in systems with large interfacial areas, such as emulsions and foams, and in processes that lead to a large increase in the interfacial area, such as electrospinning of nanofibers.

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“…The solution parameters and properties as well as process param-eters that control the fiber diameter and morphology are numerous and have been extensively investigated. [20][21][22] Parameters such as polymer concentration, molecular weight and its distribution, [23][24][25] solvent quality and volatility 26,28,29 (coupled with environmental conditions as solvent saturation 24,30,31 ), surface tension, 32 conductivity, 33 viscosity, 34,35 viscoelasticity, flow rate, distance between the electrodes (and their configuration) as well as the applied potential difference 36 (that we indicate schematically indicate in Figure 1) form a complex set of interactions. The parameters that can be controlled can generally be divided into two groups, parameters that determine the solution properties and the experimental parameters that characterise the process.…”

Section: Introductionmentioning

confidence: 99%

Dispersity and spinnability: Why highly polydisperse polymer solutions are desirable for electrospinning

Palangetic

Reddy

Srinivasan

et al. 2014

Polymer

Self Cite

116

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We develop new criteria that describe the minimum concentration limits controlling the spinnability of dilute and semi-dilute flexible polymer solutions with high molecular weight and varying polydispersity. By asserting that the finite and bounded extensional viscosity of the solution is the key material property determining the stability of a filament during spinning, we propose a new scaling relating the minimum necessary concentration of a polymer c spin to its molecular weight M and the quality of the solvent (through the excluded volume exponent n) of the form c spin ⇠ M (n+1) . This new scaling differs from the classical interpretation of the coil overlap concentration c ⇤ or entanglement concentration c e as the minimum concentration required to increase the viscosity of the spinning dope, and rationalizes the surprising spinnability of high molecular weight polymers at concentrations much lower than c e .Furthermore, we introduce the concept of an extensibility average molecular weight M L as the appropriate average for the description of polydisperse solutions undergoing an extensiondominated spinning process. In particular it is shown that this extensibility average measure, and thus the solution spinnability, is primarily determined by the extensibility of the highest molecular weight fractions. For highly polydisperse systems this leads to an effective lowering of the minimum required concentration for successful fiber spinning (in comparison to narrowly distributed polymer solutions of similar weight average molecular weights). These predictions are validated with experimental observations of the electrospinnablity of monoand polydisperse poly(methyl methacrylate) (PMMA) solutions as well as a model bimodal blend, and through comparison to published literature data on the minimum spinnable polymer concentration for a variety of flexible long chain polymers over a range of molecular weights.

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The role of interfacial viscoelasticity in the stabilization of an electrospun jet

Cited by 87 publications

References 55 publications

Interfacial viscoelasticity, yielding and creep ringing of globular protein–surfactant mixtures

Interfacial viscoelasticity, yielding and creep ringing of globular protein–surfactant mixtures

Interfacial rheology: An overview of measuring techniques and its role in dispersions and electrospinning

Dispersity and spinnability: Why highly polydisperse polymer solutions are desirable for electrospinning

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