Polyelectrolyte Brush Amplified Electroactuation of Microcantilevers

Zhou, Feng; Biesheuvel, P.M.; Choi, Eun‐Young; Shu, Wenmiao; Poetes, Rosa; Steiner, Ullrich; Huck, Wilhelm T. S.

doi:10.1021/nl073157z

Cited by 108 publications

(108 citation statements)

References 32 publications

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“…They are used in a wide range of applications including colloidal stabilization [2], responsive surface coatings [3], flocculation [4], and superabsorbent gels [5]. Very often they are responsive to external and/or environmental stimuli, such as electric fields [6,7], temperature [5,8], pH [9,10], and salt [11,12]. In recent years, polymer brushes have been shown to be a useful class of materials for many medical and biological applications [13,14].…”

Section: Introductionmentioning

confidence: 99%

Determination of the molar mass of surface-grafted weak polyelectrolyte brushes using force spectroscopy

Al-Baradi

Tomlinson

Zhang³

et al. 2015

Polymer

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The molar mass and dispersity of a polycation, poly[2-(dimethyl amino)ethyl methacrylate)] (PDMAEMA) grafted from a poly(methyl methacrylate) (PMMA) backbone, was measured by single-molecule force spectroscopy (SMFS) and shown to be consistent with results from gel permeation chromatography for the same comb polymer in aqueous solution. Comparison was then made between the comb polymer and PDMAEMA brushes that were grown from the substrate, as a function of the pH and ionic strength of the surrounding medium, and the limits of reliable characterization of the polymers are determined. A large discrepancy was observed between the responses of the comb and brush layer at low pH when the PDMAEMA molecules are extended from the supporting substrate. Here it is believed that the atomic force microscope (AFM) tip can penetrate the comb layer and selectively desorb side-chains of the comb. In the case of the well solvated PDMAEMA brushes at high pH, the tip preferentially selects larger chains, resulting in an over-estimate of the brush molar mass. The addition of salt also influenced the molar mass obtained by this technique. It is believed that salted brushes did not adhere well to the AFM tip, with subsequent desorption resulting in an underestimate of the molar mass. However, SMFS was shown to be capable of demonstrating the effect of salt on brush conformation, with greater swelling after the addition of a small amount of NaCl, but a significant decrease when 100 mM is added.

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Section: Introductionmentioning

confidence: 99%

Determination of the molar mass of surface-grafted weak polyelectrolyte brushes using force spectroscopy

Al-Baradi

Tomlinson

Zhang³

et al. 2015

Polymer

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“…[1][2][3][4][5][6][7]. The controlled/living character of the polymerization allows for the creation of well-defined films even providing block-copolymer compositions with a controlled thickness for a widespread of applications e.g., in antimicrobial [8,9] and protective coatings preventing adsorption of plasma proteins and platelets [10,11], protein affinity layers [12,13] and responsive films [14,15]. In these applications, precise control over the polymerization properties is imperative since delicate changes can result in repulsion layers or affinity layers [16].…”

Section: Introductionmentioning

confidence: 99%

Surface Initiated Polymerizations via e-ATRP in Pure Water

Hosseiny

Rijn

2013

Polymers

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Abstract:Here we describe the combined process of surface modification with electrochemical atom transfer radical polymerization (e-ATRP) initiated from the surface of a modified gold-electrode in a pure aqueous solution without any additional supporting electrolyte. This approach allows for a very controlled growth of the polymer chains leading towards a steady increase in film thickness. Electrochemical quartz crystal microbalance displayed a highly regular increase in surface confined mass only after the addition of the pre-copper catalyst which is reduced in situ and transformed into the catalyst. Even after isolation and washing of the modified electrode surface, reinitiation was achieved with retention of the controlled electrochemical ATRP reaction. This reinitiation after isolation proves the livingness of the polymerization. This approach has interesting potential for smart thin film materials and offers also the possibility of post-modification via additional electrochemical induced reactions.

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“…Schematic diagram showing a proposed negatively end-charged polymer brush system, which is stretched at negative surface charge and collapsed (looped) at positive surface charge. [65] demonstrated that AFM microcantilevers grafted on one side with a poly[2-(methacrylolyloxy)ethyl] trimethyl ammonium chloride (PMETAC) strong polyelectrolyte brush layer could be actuated by the application of a voltage between the tip holder and a remote electrode within a liquid cell containing weak salt solutions. This effect has been explained by the surface stresses due to voltage-induced conformational changes within the polyelectrolyte brush layers.…”

Section: Voltage Electric Field or Electrochemical Response: Presenmentioning

confidence: 99%

Water Soluble Responsive Polymer Brushes

Weir

Parnell

2011

Polymers

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Abstract:Responsive polymer brushes possess many interesting properties that enable them to control a range of important interfacial behaviours, including adhesion, wettability, surface adsorption, friction, flow and motility. The ability to design a macromolecular response to a wide variety of external stimuli makes polymer brushes an exciting class of functional materials, and has been made possible by advances in modern controlled polymerization techniques. In this review we discuss the physics of polymer brush response along with a summary of the techniques used in their synthesis. We then review the various stimuli that can be used to switch brush conformation; temperature, solvent quality, pH and ionic strength as well as the relatively new area of electric field actuation We discuss examples of devices that utilise brush conformational change, before highlighting other potential applications of responsive brushes in real world devices.

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Polyelectrolyte Brush Amplified Electroactuation of Microcantilevers

Cited by 108 publications

References 32 publications

Determination of the molar mass of surface-grafted weak polyelectrolyte brushes using force spectroscopy

Determination of the molar mass of surface-grafted weak polyelectrolyte brushes using force spectroscopy

Surface Initiated Polymerizations via e-ATRP in Pure Water

Water Soluble Responsive Polymer Brushes

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