Weak Polyacid Brushes:  Preparation by LB Deposition and Optically Detected Titrations

Currie, E.P.K.; Sieval, Alexander B.; Avena, Marcelo Javier; Zuilhof, Han; Sudhölter, E.J.R.; Stuart, Martien A. Cohen

doi:10.1021/la990689p

Cited by 112 publications

(156 citation statements)

References 12 publications

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“…In fact, the size of features in the SFM images matches exactly with the calculated area/molecule deposited with the LB trough further supporting an average molecular weight of the comb molecules as being around 130 kDa. Some research into creating dense layers via amphiphilic copolymer LB assembly has been performed in the past [26][27][28][29][30][31][32][33][34][35], but we have shown that multi-molecular micellation (creating structures > 100 nm) has been largely prevented through controlling polymer chain architecture. Such films could potentially be used as ultrathin size-selective nanofiltration films for sensor applications, templates for nanolithography, or an environmentally acceptable way to tune the physical and chemical properties of a flat surface.…”

Section: Preparation Of Langmuir-blodgett (Lb) and Langmuir-schäfer (mentioning

confidence: 96%

Creation of dense polymer brush layers by the controlled deposition of an amphiphilic responsive comb polymer

Tomlinson

Cousin

Geoghegan

2009

Polymer

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Section: Preparation Of Langmuir-blodgett (Lb) and Langmuir-schäfer (mentioning

confidence: 96%

Creation of dense polymer brush layers by the controlled deposition of an amphiphilic responsive comb polymer

Tomlinson

Cousin

Geoghegan

2009

Polymer

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“…Finally, the wafers were heated at 110 1C for 10 min which leads to a diffusion of the PS chains of the PS-PAA molecules into the d-PS films thereby creating stable and irreversibly fixed PAA brushes. 36 …”

Section: à2mentioning

confidence: 99%

Salt-induced protein resistance of polyelectrolyte brushes studied using fluorescence correlation spectroscopy and neutron reflectometry

Czeslik

Jackler

Hazlett

et al. 2004

Phys. Chem. Chem. Phys.

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We used two-photon excitation fluorescence correlation spectroscopy (FCS) and neutron reflectometry to study in situ the effect of salt concentration on the degree of protein binding to polyelectrolyte brushes. The binding of bovine serum albumin (BSA) to poly(acrylic acid) (PAA) brushes was characterized at neutral pH values where both the protein and the brushes carry a negative charge. Spherical PAA brush particles were used in the FCS experiments, whereas a planar PAA brush served as protein substrate in the neutron reflectometry experiments. It has been found that BSA binds strongly to both the spherical and the planar PAA brushes under electrostatic repulsion at low ionic strength. The BSA volume fraction profile, as determined from the neutron reflectivities, indicates a deep penetration of the BSA molecules into the PAA brush. However, the analysis of the FCS data reveals that the protein affinity of the spherical PAA brush particles decreases drastically when increasing the concentration of sodium chloride to a few 100 mM. This observation is in line with the measured neutron reflectivities of the planar PAA brush. The reflectivity curve obtained in the absence of protein is virtually overlapping with that measured when the PAA brush is in contact with a BSA solution but containing 500 mM sodium chloride which suggests protein resistance of the planar PAA brush at this elevated salt concentration. The results of this study provide evidence for a new kind of protein-resistant interfaces. Whereas protein binding to the PAA brush is likely to be dominated by the release of counterions, this driving force vanishes as the ionic strength of the solution is raised and protein molecules are repelled from the interface by steric interactions. In a general view, the ''switching'' of the protein affinity of a PAA brush by varying the ionic strength of the protein solution over a relatively small range may appear to be useful for biotechnological applications.

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“…This technique has been applied to brushes prepared using both grafting-to 8,10,[35][36][37] and grafting-from methods. Recently, a number of studies have been performed of grafted-from brushes prepared using methacrylate ATRP, focusing on a variety of weak pH-responsive brushes 11,21,34,38,39 , as well as strong polyelectrolyte brushes 21,40,41 and polyampholytes 22 .…”

Section: Introductionmentioning

confidence: 99%

Structure and Collapse of a Surface-Grown Strong Polyelectrolyte Brush on Sapphire

et al. 2012

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We have used neutron reflectometry to investigate the behavior of a strong polyelectrolyte brush on a sapphire substrate, grown by atom transfer radical polymerization (ATRP) from a silane-anchored initiator layer. The initiator layer was deposited from vapor, following treatment of the substrate with an Ar/H 2 O plasma to improve surface reactivity. The deposition process was characterized using X-ray reflectometry, indicating the formation of a complete, cross-linked layer. The brush was grown from the monomer [2-(methacryloyloxy)ethyl]trimethylammonium chloride (METAC), which carries a strong positive charge. The neutron reflectivity profile of the swollen brush in pure water (D 2 O) showed that it adopted a two-region structure, consisting of a dense surface region ∼ 100 Å thick, in combination with a diffuse brush region extending to around 1000 Å from the surface. The existence of the diffuse brush region may be attributed to electrostatic repulsion from the positively-charged surface region, while the surface region itself most probably forms due to polyelectrolyte adsorption to the hydrophobic initiator layer. The importance of electrostatic interactions in maintaining the brush region is confirmed by measurements at high (1 M) added 1:1 electrolyte, which show a substantial transfer of polymer from the brush to the surface region, together with a strong reduction in brush height. On addition of 10 -4 M oppositely-charged surfactant (sodium dodecyl sulfate SDS), the brush undergoes a dramatic collapse, forming a single dense layer about 200 Å in thickness, which may be attributed to the neutralization of the monomers by adsorbed dodecyl sulfate ions in combination with hydrophobic interactions between these dodecyl chains. Subsequent increases in surfactant concentration result in slow increases in brush height, which may be caused by stiffening of the polyelectrolyte chains due to further dodecyl sulfate adsorption.3

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Weak Polyacid Brushes: Preparation by LB Deposition and Optically Detected Titrations

Cited by 112 publications

References 12 publications

Creation of dense polymer brush layers by the controlled deposition of an amphiphilic responsive comb polymer

Creation of dense polymer brush layers by the controlled deposition of an amphiphilic responsive comb polymer

Salt-induced protein resistance of polyelectrolyte brushes studied using fluorescence correlation spectroscopy and neutron reflectometry

Structure and Collapse of a Surface-Grown Strong Polyelectrolyte Brush on Sapphire

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