Polymer Bridging Probed by Magnetic Colloids

Cohen-Tannoudji, Laetitia; Bertrand, Emanuel; Bressy, Lydie; Goubault, Cécile; Baudry, Jean; Klein, Jacob; Joanny, Jean‐François; Bibette, Jérôme

doi:10.1103/physrevlett.94.038301

Cited by 54 publications

(47 citation statements)

References 14 publications

(16 reference statements)

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“…For PAA in bulk solution, this increase in charge density causes the polymer to adopt an extended conformation due to charge-charge repulsion between carboxylate functional groups (29,30). Titrations in this laboratory show the bulk pK a of PAA to be 6, which is in agreement with literature (31)(32)(33)(34)(35). The pK a value of aPMA, and therefore likely iPMA, is reported to be 7.3 (36).…”

Section: Adsorption Of Paa To the Oil-water Interfacesupporting

confidence: 78%

Ordered polyelectrolyte assembly at the oil–water interface

Beaman

Robertson

Richmond

2012

Proc. Natl. Acad. Sci. U.S.A.

107

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Polyelectrolytes (PEs) are widely used in applications such as water purification, wastewater treatment, and mineral recovery. Although much has been learned in past decades about the behavior of PEs in bulk aqueous solutions, their molecular behavior at a surface, and particularly an oil-water interface where many of their applications are most relevant, is largely unknown. From these surface spectroscopic and thermodynamics studies we report the unique molecular characteristics that several common polyelectrolytes, poly(acrylic acid) and poly(methylacrylic acid), exhibit when they adsorb at a fluid interface between water and a simple insoluble organic oil. These PEs are found to adsorb to the interface from aqueous solution in a multistepped process with a very thin initial layer of oriented polymer followed by multiple layers of randomly oriented polymer. This additional layering is thwarted when the PE conformation is constrained. The adsorption/desorption process is highly pH dependent and distinctly different than what might be expected from bulk aqueous phase behavior. macromolecular assembly | surface spectroscopy | water surfaces | hydrophobic surfaces | surfactants

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Section: Adsorption Of Paa To the Oil-water Interfacesupporting

confidence: 78%

Ordered polyelectrolyte assembly at the oil–water interface

Beaman

Robertson

Richmond

2012

Proc. Natl. Acad. Sci. U.S.A.

107

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“…[18] Note finally that the present elongated and stiff structures bear some similarities with the filaments of magnetic microbeads recently designed for biomedical applications. [19] The main differences here are the sizes of the initial particles and the stiffness of the final constructs. Assuming a volume fraction of magnetic material inside the rods of 0.20, [8] we have estimated the linear density of particles at 5 Â 10 4 mm…”

mentioning

confidence: 99%

Electrostatic Co‐Assembly of Iron Oxide Nanoparticles and Polymers: Towards the Generation of Highly Persistent Superparamagnetic Nanorods

Fresnais¹,

Berret²,

et al. 2008

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“…This elastic filament consists of superparamagnetic micron-sized beads that are linked together by pieces of double-stranded DNA [27,28]. The flagellum is actuated by an oscillating magnetic field so that it drags an attached red-blood cell forward.…”

Section: Introductionmentioning

confidence: 99%

Fluid transport at low Reynolds number with magnetically actuated artificial cilia

2008

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Abstract. By numerical modeling we investigate fluid transport in low-Reynolds-number flow achieved with a special elastic filament or artifical cilium attached to a planar surface. The filament is made of superparamagnetic particles linked together by DNA double strands. An external magnetic field induces dipolar interactions between the beads of the filament which provides a convenient way of actuating the cilium in a well-controlled manner. The filament has recently been used to successfully construct the first artificial micro-swimmer [R. Dreyfus at al., Nature 437, 862 (2005)]. In our numerical study we introduce a measure, which we call pumping performance, to quantify the fluid transport induced by the magnetically actuated cilium and identify an optimum stroke pattern of the filament. It consists of a slow transport stroke and a fast recovery stroke. Our detailed parameter study also reveals that for sufficiently large magnetic fields the artificial cilium is mainly governed by the Mason number that compares frictional to magnetic forces. Initial studies on multi-cilia systems show that the pumping performance is very sensitive to the imposed phase lag between neighboring cilia, i.e., to the details of the initiated metachronal wave.

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Polymer Bridging Probed by Magnetic Colloids

Cited by 54 publications

References 14 publications

Ordered polyelectrolyte assembly at the oil–water interface

Ordered polyelectrolyte assembly at the oil–water interface

Electrostatic Co‐Assembly of Iron Oxide Nanoparticles and Polymers: Towards the Generation of Highly Persistent Superparamagnetic Nanorods

Fluid transport at low Reynolds number with magnetically actuated artificial cilia

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