Synthesis and swelling behavior of a weak polyacid brush

Biesalski, Markus; Johannsmann, Diethelm; Rühe, Jürgen

doi:10.1063/1.1490924

Cited by 161 publications

(214 citation statements)

References 24 publications

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“…7) 22,23 , which predicts that the brush should collapse with increasing salt concentration (C), but only as a relatively weak power law (C À 1/3 ). We see a comparatively steeper ionic strength-dependence, which has been previously observed in synthetic polymer systems [24][25][26][27][28][29] and may arise from the local modulation of protein charge-based interactions due to added salt. At pH 10.9, below a critical ionic strength (B2 mM), the system enters an 'osmotic brush' regime in which the brush height increases with ionic strength.…”

Section: Resultsmentioning

confidence: 58%

Stimuli-sensitive intrinsically disordered protein brushes

et al. 2014

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Grafting polymers onto surfaces at high density to yield polymer brush coatings is a widely employed strategy to reduce biofouling and interfacial friction. These brushes almost universally feature synthetic polymers, which are often heterogeneous and do not readily allow incorporation of chemical functionalities at precise sites along the constituent chains. To complement these synthetic systems, we introduce a biomimetic, recombinant intrinsically disordered protein that can assemble into an environment-sensitive brush. This macromolecule adopts an extended conformation and can be grafted to solid supports to form oriented protein brushes that swell and collapse dramatically with changes in solution pH and ionic strength. We illustrate the value of sequence specificity by using proteases with mutually orthogonal recognition sites to modulate brush height in situ to predictable values. This study demonstrates that stimuli-responsive brushes can be fabricated from proteins and introduces them as a new class of smart biomaterial building blocks.

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Section: Resultsmentioning

confidence: 58%

Stimuli-sensitive intrinsically disordered protein brushes

et al. 2014

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“…In addition, the degree of dissociation of the monomer units increased toward the brush end that extended into the solution. In a separate study, the existence of this maximum was experimentally verified for poly(methacrylic acid) brushes [21]. Although the precise grafting density of the chains was unknown, this maximum occurred at 0.002 M of NaNO 3 .…”

Section: Pdmaema Comb and Brush Behaviour In Salt Solutionsmentioning

confidence: 97%

“…This is usually due to changes in the osmotic pressure caused by the presence of counterions within the brush layer [21]. The swelling behaviour of such systems exhibits some notable characteristics depending on the pH of the solvent, concentration and type of ions in the solution, and the grafting density of the brush.…”

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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“…Neutral polymer brushes and polyelectrolyte brushes are widely used for the modification of surfaces, due to their advantageous specific properties, such as mechanical and chemical stability, their adsorption behavior [1] and permeability [2] and the possibility to tune their structure by varying external stimuli. For instance, the structure of a weak polyelectrolyte brush depends on pH [3][4][5][6][7][8], temperature [9][10][11], salt [12][13][14][15] and solvent [16][17][18]. More precisely, the swelling/shrinking of the studied poly-(N,N-(dimethylamino ethyl) methacrylate) (PDMAEMA) brushes can be manipulated by adjusting the pH of the surrounding environment to values below and above the pK A .…”

Section: Introductionmentioning

confidence: 99%

Stimuli-Responsive Polyelectrolyte Brushes As a Matrix for the Attachment of Gold Nanoparticles: The Effect of Brush Thickness on Particle Distribution

et al. 2014

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The effect of brush thickness on the loading of gold nanoparticles (AuNPs) within stimuli-responsive poly-(N,N-(dimethylamino ethyl) methacrylate) (PDMAEMA) polyelectrolyte brushes is reported. Atom transfer radical polymerization (ATRP) was used to grow polymer brushes via a "grafting from" approach. The brush thickness was tuned by varying the polymerization time. Using a new type of sealed reactor, thick brushes were synthesized. A systematic study was performed by varying a single parameter (brush thickness), while keeping all other parameters constant. AuNPs of 13 nm in diameter were attached by incubation. X-ray reflectivity, electron scanning microscopy and ellipsometry were used to study the particle loading, particle distribution and interpenetration of the particles within the brush matrix. A model for the structure of the brush/particle hybrids was derived. The particle number densities of attached AuNPs depend on the brush thickness, as do the optical properties of the hybrids. An increasing particle number density was found for increasing brush thickness, due to an increased surface roughness.

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Synthesis and swelling behavior of a weak polyacid brush

Cited by 161 publications

References 24 publications

Stimuli-sensitive intrinsically disordered protein brushes

Stimuli-sensitive intrinsically disordered protein brushes

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

Stimuli-Responsive Polyelectrolyte Brushes As a Matrix for the Attachment of Gold Nanoparticles: The Effect of Brush Thickness on Particle Distribution

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