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Initial-Stage Dynamics of Flocculation of Cationic Colloidal Particles Induced by Negatively Charged
Leonid O Ilyasov1, Kazuyoshi Ogawa2, Irina G Panova1
1Department of Chemistry, Lomonosov Moscow State University, Leninskie gory 1-3, Moscow 119991, Russia.
Langmuir : the ACS Journal of Surfaces and Colloids
|July 2, 2020
Summary
Polyelectrolytes (PEs) and polyelectrolyte complexes (PECs) were studied for their flocculation dynamics. Microgel concentration impacts flocculation less than linear polymer concentration, with instant aggregation observed.
Area of Science:
- Colloid and Surface Science
- Polymer Chemistry
- Materials Science
Background:
- Flocculation dynamics of positively charged latex particles are influenced by polyelectrolytes (PEs) and polyelectrolyte complexes (PECs).
- Understanding the initial stages of flocculation is crucial for controlling particle aggregation.
- Linear polyacrylic acid (PAA) and a PAA-based microgel (PAA#) with a polycation were used to form PECs.
Purpose of the Study:
- To comparatively analyze the initial-stage flocculation dynamics induced by linear PEs and PECs.
- To investigate the influence of microgel structure and concentration on flocculation rates.
- To explore the role of instant aggregation in microgel-induced flocculation.
Main Methods:
- Standardized colloidal mixing procedure to assess flocculation rates.
- Comparative analysis of flocculation dynamics using linear polymers and microgel-based PECs.
- Investigation of initial flocculation rates immediately after onset.
Main Results:
- Flocculation rates with linear polyanions were similar to those observed with negatively charged colloids and positively charged PEs.
- Microgel concentration had a less pronounced effect on the initial flocculation rate compared to linear polymer concentration.
- A significant increase in the initial flocculation rate was observed due to instant aggregation of the negatively charged microgel induced by polycation adsorption.
Conclusions:
- The three-dimensional structure of microgels influences flocculation dynamics differently than linear polymers.
- Polycation adsorption onto negatively charged microgels can induce rapid aggregation, significantly increasing flocculation rates.
- The state and formation dynamics of PECs before interacting with target particles are critical for effective flocculation and require further investigation.
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