Wetting of nanofiber yarns

Tsai, Chen-Chih; Gu, Yu; Kornev, Konstantin G.

doi:10.1016/j.colsurfa.2014.06.037

Cited by 16 publications

(11 citation statements)

References 46 publications

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“…The effects of nano- and micro-scale roughness/texture on the wetting of solids have been studied extensively in recent years. − Classic models of wetting, e.g., the Young, Wenzel, and Cassie–Baxter models, which are elaborated below, are commonly used to rationalize experimental observations, usually a posteriori rather than a priori . The Young equation (Figure A) describes the equilibrium contact angle on atomically smooth, flat, and nondeformable surfaces.…”

Section: Introductionmentioning

confidence: 99%

Simple-to-Apply Wetting Model to Predict Thermodynamically Stable and Metastable Contact Angles on Textured/Rough/Patterned Surfaces

Kaufman

Chen²,

Mishra

et al. 2017

J. Phys. Chem. C

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Rough/patterned/textured surfaces with nano/microcavities that broaden below the surfaceknown as "re-entrants"can be omniphobic (macroscopic contact angle greater than 90°for both water and oils). The existing theoretical models that explain the effects of texture on wetting are complex and do not provide a simple procedure for predicting the thermodynamically stable and metastable states and their corresponding contact angles (for example, wetting states that involve partially filled cavities). Here, we develop a simple-to-apply wetting model that allows for (1) predicting a priori the wetting state (partially or fully filled) of the cavities both under and outside the liquid droplet and the corresponding macroscopic contact angles on any type of textured surface; (2) determining the conditions under which metastable states exist; and (3) engineering specific nano/microtextures that yield any desired macroscopic contact angle, θ t , for a given intrinsic contact angle θ 0. Subsequently, we experimentally demonstrate how one can use the model to predict the metastable and the thermodynamically stable contact angles on nondeformable textured surfaces consisting of arrays of axisymmetric cavities/protrusions. In this model, we do not consider the effects of gravitational forces, Laplace pressure of the droplet, line tension, droplet impact velocity, and quantitative aspects of contact angle hysteresis. Nonetheless, the model is suitable for accurately predicting the contact angles of macroscopic droplets (droplet volume ∼1 μL and base diameters <2 mm), which is of immense relevance in engineering. In the experimental section we also discuss the suitability of the model to be extended in order to include the effects of contact angle hysteresis on the macroscopic apparent contact angle on textured surfaces. Controlling these macroscopic contact angles, whether higher or lower than the intrinsic angle, θ 0 , is desirable for many applications including nonwetting, self-cleaning, and antifouling surfaces and for completely wetting/spreading applications, such as creams, cosmetics, and lubricant fluids.

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Section: Introductionmentioning

confidence: 99%

Simple-to-Apply Wetting Model to Predict Thermodynamically Stable and Metastable Contact Angles on Textured/Rough/Patterned Surfaces

Kaufman

Chen²,

Mishra

et al. 2017

J. Phys. Chem. C

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“…To develop a suture with improved resistance to thrombosis, we propose to take advantage of the high surface area provided by electrospun nanofibers for binding and release of antithrombotic drugs. − Existing technologies allow electrospinning of highly aligned nanofibers that can be subsequently bundled or twisted to form nanofiber yarns. ,− Since the first report of the fabrication of electrospun nanofibers as a delivery carrier for the model drug tetracycline, many studies have investigated drug delivery from nanofibers. Drug loading can be achieved by (1) dissolving or dispersing the drugs in polymer solutions, resulting in one-phase nanofibers or (2) conjugating the drugs directly onto the polymers for a sustained or stimuli-responsive drug release or (3) using multiaxial needles to develop multiphase nanofibers. ,− For example, Lu et al developed cationized gelatin-coated polycaprolactone fibers by coaxial electrospinning for constructing a core–shell fibrous membrane and immobilized the heparin/vascular endothelial growth factor (VEGF) complex through ionic interactions .…”

Section: Introductionmentioning

confidence: 99%

Heparin-Eluting Electrospun Nanofiber Yarns for Antithrombotic Vascular Sutures

Bae

DiBalsi²,

Meilinger³

et al. 2018

ACS Appl. Mater. Interfaces

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The surgical connection of blood vessels, anastomosis, is a critical procedure in many reparative, transplantation, and reconstructive surgical procedures. However, effective restoration of circulation is complicated by pathological clotting (thrombosis) or progressive occlusion due to excess cell proliferation that often leads to additional surgeries and increases morbidity and mortality risk for patients. Pharmaceutical agents have been tested to prevent these complications, but many have unacceptable systemic side effects. Therefore, an alternative approach to deliver these drugs at the site of injury in a controlled manner is necessary. The objective of this study was to develop electrospun nanofibers composed of polyester poly(lactide- co-glycolide) (PLGA), poly(ethylene oxide) (PEO), and positively charged copolymer, poly(lactide- co-glycolide)- graft-polyethylenimine (PgP) for electrostatic binding and release of heparin for application as an antithrombotic microvascular suture. PgP was synthesized with different coupling ratios between PLGA and branched polyethylenimine (bPEI) to obtain PgP (∼1 PLGA grafted to 1 bPEI) and PgP (∼3.7 PLGA grafted to 1 bPEI). Nanofiber yarns (PLGA/PEO/PgP and PLGA/PEO/PgP) were fabricated by electrospinning. Heparin immobilization on the positively charged nanofiber yarns was visualized using fluorescein-conjugated heparin (F-Hep), and the amount of immobilized F-Hep was higher on both PLGA/PEO/PgP and PLGA/PEO/PgP than yarns without PgP (PLGA/PEO). We also found that F-Hep was released from both PgP-containing yarns in a sustained manner over 20 days, while over 60% of F-Hep was released within 4 h from PLGA/PEO. Finally, we observed that heparin-eluting nanofiber yarns with both PgP and PgP showed significantly longer clotting times than nanofiber yarns without PgP. The clotting time of PLGA/PEO/PgP was not significantly different than that of free heparin (0.5 μg/mL). These results show that heparin-eluting electrospun nanofiber yarns may offer a basis for the development of microvascular sutures with anticoagulant activity.

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“…We studied the capillary effect of a liquid film associated with a flexed or coiled proboscis to answer the question of how coiling and bending the proboscis might benefit the insect. An understanding of wetting phenomena of complexly shaped fibres is relevant not only to insect biology but also to materials engineering [12][13][14][30][31][32][33][34][35][36]. We examine the stability of liquid films on a hollow fibre, with elliptical cross section, coiled in a ring.…”

Section: Introductionmentioning

confidence: 99%

“…These considerations help to understand the effect of concave-convex bends on the pressure distribution in the film.As an illustration of these findings, we traced the evolution of thin glycerin films deposited on nylon fishing line (Berkley Trilene ® Super Strong™, diameter 0.28 mm) looped for different radii of curvature (figure8). Using the capillary rise experiment as discussed in[32], we obtained the contact angle of 31°for glycerin on these fibres. The loops were vertically withdrawn from a glycerin reservoir with the liquid completely covering the entire surface.…”

mentioning

confidence: 99%

Effect of curvature on wetting and dewetting of proboscises of butterflies and moths

et al. 2018

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Proboscises of butterflies are modelled as elliptical hollow fibres that can be bent into coils. The behaviour of coating films on such complex fibres is investigated to explain the remarkable ability of these insects to control liquid collection after dipping the proboscis into a flower or pressing and mopping it over a food source. By using a thin-film approximation with the air–liquid interface positioned almost parallel to the fibre surface, capillary pressure was estimated from the profile of the fibre surfaces supporting the films. The film is always unstable and the proboscis shape and movements have adaptive value in collecting fluid: coiling and bending of proboscises of butterflies and moths facilitate fluid collection. Some practical applications of this effect are discussed with regard to fibre engineering.

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Wetting of nanofiber yarns

Cited by 16 publications

References 46 publications

Simple-to-Apply Wetting Model to Predict Thermodynamically Stable and Metastable Contact Angles on Textured/Rough/Patterned Surfaces

Simple-to-Apply Wetting Model to Predict Thermodynamically Stable and Metastable Contact Angles on Textured/Rough/Patterned Surfaces

Heparin-Eluting Electrospun Nanofiber Yarns for Antithrombotic Vascular Sutures

Effect of curvature on wetting and dewetting of proboscises of butterflies and moths

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