pH-Controlled assembly of polyelectrolyte layers on silica nanoparticles in concentrated suspension
Journal article, 2022

Hypothesis: Preparation of suspensions of nanoparticles (>1 wt%) coated with a polyelectrolyte multilayers is a challenging task because of the risk of flocculation when a polyelectrolyte is added to a suspension of oppositely charged nanoparticles. This situation can be avoided if the charge density of the polymers and particles is controlled during mixing so as to separate mixing and adsorption events. Experiments: The cationic polyethylenimine (PEI) and the anionic carboxymethylcellulose (CMC) were used as weak polyelectrolytes. Polyelectrolyte multilayers build-up was conducted by reducing the charge of one of the components during the addition of the next component. Charge density was controlled by tuning pH. Analysis of the suspension of coated nanoparticles was done by means of dynamic light scattering, electrophoresis and small angle x-ray scattering measurements, while quartz crystal microbalance was used to study the build-up process on flat silica surfaces. Findings: Charge density, controlled through pH, can be used as a tool to avoid flocculation during layer-by-layer deposition of polyelectrolytes on 20 nm silica particles at high concentration (∼40 wt%). When added to silica at pH 3, PEI did not induce flocculation. Adsorption was triggered by raising the pH to 11, pH at which CMC could be added. The pH was then lowered to 3. The process was repeated, and up to five polyelectrolyte layers were deposited on concentrated silica nanoparticles while inducing minimal aggregation.

Silica

Polyelectrolyte

Polyelectrolyte layers

Adsorption

Controlled assembly

Concentrated suspension

Aggregation

Nanoparticle

Author

Krzysztof Kolman

Applied Surface Chemistry

Nouryon Surface Chemistry AB

Giovanna Poggi

University of Florence

M. Baglioni

University of Florence

D. Chelazzi

University of Florence

P. Baglioni

University of Florence

Michael Persson

Chalmers, Chemistry and Chemical Engineering, Energy and Material

Nouryon Pulp and Performance Chemicals AB

Krister Holmberg

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Romain Bordes

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Journal of Colloid and Interface Science

0021-9797 (ISSN) 1095-7103 (eISSN)

Vol. 615 265-272

NANOmaterials for the REStoration of works of ART (NANORESTART)

European Commission (EC) (EC/H2020/646063), 2015-06-01 -- 2018-12-31.

Subject Categories

Physical Chemistry

Materials Chemistry

Other Chemistry Topics

DOI

10.1016/j.jcis.2022.01.120

PubMed

35144228

More information

Latest update

3/10/2022