Structure of a Diblock Copolymer Adsorbed at the Hydrophobic Solid/Aqueous Interface:  Effects of Charge Density on a Weak Polyelectrolyte Brush

Abstract

We have used neutron reflection to study the effects of pH and added electrolyte on the structure of a weak polyelectrolyte brush anchored by means of a hydrophobic block to a hydrophobic surface. The copolymer was poly(2-(dimethylamino)ethyl methacrylate-block-methyl methacrylate) (poly(DMAEMA-b-MMA)) containing 70% DMAEMA and having a molecular weight of 10000. The MMA block and the hydrophobic octadecyltrichlorosilane (OTS) layer were deuterated in order to highlight the DMAEMA fraction of the layer. The MMA block was found to bind strongly and irreversibly to a self-assembled monolayer of octadecyl trichlorosilane (OTS) on silica. The copolymer distribution could be described in terms of two uniform layers, a thin layer next to the surface containing all the MMA block and variable amounts of the DMAEMA residues with a copolymer volume fraction of about 0.8 and a more diffuse block corresponding to the polyelectrolyte brush. The presence of DMAEMA residues in the thin layer and the variation of this amount with pH and added electrolyte show that, near the anchor layer of the MMA block, the DMAEMA block is not ionized, in agreement with the model of a grafted weak polyelectrolyte proposed by Israels et al.

Nanoscopic Polymer Particles with a Well‐Defined Surface: Synthesis, Characterization, and Properties

“…Annealed brushes affixed to planar surfaces have therefore been the subject of intense theoretical research, [40,41,[43][44][45][46][47][48][49] while the number of experimental studies devoted to these systems is still rather small. [53][54][55][56][57][58][59] …”

“…[53][54][55][56][57][58][59][60] A review of this work has been given recently by Dubreuil and Guenon. [60] The term brush denotes a planar or curved surface onto which linear polymer or polyelectrolyte chains are grafted densely.…”

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

“…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 .…”

Characterizations and properties of hairy latex particles

“…The adsorption process is mainly governed by the affinity for the surface and the solvency. The introduction of an additional electrostatic component by adsorbing polyelectrolytes [10,11] increases the stability of the suspension when the architecture is adapted. But the stabilization by physisorption is extremely dependent on variations of the medium.…”