Specific ζ-Potential Response of Layer-by-Layer Coated Colloidal Particles Triggered by Polyelectrolyte Ion Interactions

Abstract

The zeta-potential of PSS/PAH and PSS/PDADMAC coated silica particles was studied in the presence of ClO4(-) and H2PO4(-) salts. In the presence of ClO4(-), layer-by-layer (LbL) coated silica particles with PDADMAC as the top layer show a reversal in the surface charge with increasing salt concentration but remain positive in phosphate solutions. LbL particles with PAH as the top layer become, however, negative in the presence of H2PO4(-) but retain their positive charge in the presence of ClO4(-). Charge reversal was explained by specific interaction of ClO4(-) ions with the quaternary amine groups and of H2PO4(-) with the primary amines through hydrogen bonding. Atomic force microscopy (AFM) and quartz crystal microbalance with dissipation (QCM-D) were employed to study the corresponding layer stability on planar surfaces.

Phosphate‐Responsive Biomimetic Nanofluidic Diodes Regulated by Polyamine–Phosphate Interactions: Insights into Their Functional Behavior from Theory and Experiment

“…P‐NMR studies have revealed that interactions with phosphates occur in the whole range of pH where a typical synthetic polyamine, polyallylamine (PAH), is protonated and phosphate is anionic (≈4–9) . On the other hand, this specific interaction between polyamines and phosphates was reported to reverse the surface charge in layer‐by‐layer polyelectrolyte multilayers . Furthermore, the specific adsorption of phosphate anions onto amino‐terminated self‐assembled‐monolayers, partially reversing the surface charge and even enhancing the adsorption of positively charged proteins, was demonstrated …”

“…[17] On the other hand, this specific interaction between polyamines and phosphates was reported to reverse the surface charge in layerby-layer polyelectrolyte multilayers. [18] Furthermore, the specific adsorption of phosphate anions onto amino-terminated selfassembled-monolayers, partially reversing the surface charge and even enhancing the adsorption of positively charged proteins, was demonstrated. [19] Learning about the physicochemical nature of the interaction between phosphates and polyamines and how it behaves within nanoconfined environments is the first step in understanding these fundamental biological interactions and in devising new types of synthetic biosensors for phosphate-bearing molecules.…”

Luminescence Enhancement of ZnS:Cu Nanocrystals by Zinc Sulfide Coating with Core/Shell Structure

“…According to the layer by layer formation mechanism has been applied successfully on fabrication of nanocomposites with thin layer [28,29], the similar method was used for coating ZnS shell on ZnS:Cu core. The formation mechanism of ZnS shells coated on the surface of ZnS:Cu NCs can be explained as follows: Firstly, because of the molar ratio of reactant (nS/nZn>1), many S 2− dangling bonds were existed on the surface of ZnS:Cu NCs (Fig.…”

Holes and Ledges Created by Multilayer Assembly on Polyelectrolyte Brushes: A Novel Route for the Three‐Dimensional Nanoscale Design of Surfaces

“…LBL films have been employed for the coating of colloids and thereof fabrication of micro and nanocapsules, [10] the fabrication of membranes for reverse osmosis, [11] or just as a versatile tool for the non-covalent modification of surfaces. [12] LBL films can be assembled on a large variety of charged surfaces including polyelectrolyte brushes.…”