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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Aggregation Behavior of Asymmetric Diblock Polyampholyte in Aqueous Solution over a Wide Range of pH and Ionic Strength

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Author(s):
Trindade, Suelen G. [1] ; da Silveira, Nadya P. [2] ; Loh, Watson [1]
Total Authors: 3
Affiliation:
[1] Univ Campinas UNICAMP, Inst Chem, POB 6154, BR-13083970 Campinas, SP - Brazil
[2] Fed Univ Rio Grande do Sul UFRGS, Inst Chem, POB 9500, BR-90650001 Porto Alegre, RS - Brazil
Total Affiliations: 2
Document type: Journal article
Source: MACROMOLECULAR CHEMISTRY AND PHYSICS; v. 222, n. 19 SEP 2021.
Web of Science Citations: 0
Abstract

The aggregation behavior of the asymmetric diblock polyampholyte poly(2-(dimethylamino)ethyl methacrylate-block-poly(acrylic acid) (PDMAEMA(86)-b-PAA(24)) is studied by static and dynamic light scattering techniques (S/DLS) in aqueous solutions. The molecular assemblies formed by this copolymer are monitored in pure water and over a wide pH range. At pH 5.5, where both blocks are ionized, spherical polymer micelles with hydrodynamic radius (R-H) around 124 nm are detected. These micelles are composed of a large and highly hydrated core formed by the electrostatic complexation between the oppositely charged blocks, and a corona formed by the uncompensated cationic PDMAEMA chains. By combining the results of light scattering, small angle X-ray scattering (SAXS), and cryogenic transmission eletron microscopy (Cryo-TEM) techniques and the predictions of theoretical models from the literature, an aggregation model is proposed, similar to already described crew-cut micelles. These aggregates display resistance to high ionic strengths, suggesting a transition from electrostatic to hydrophobic intermolecular interactions accounting for micelle formation, which is confirmed by the increased incorporation of a hydrophobic probe. The persistence of the aggregates even in conditions at which one of the blocks displays no charge (at extreme pH values) or with high salt concentration, is attributed to remaining hydrogen bonding or hydrophobic interactions that contribute to the core formation. (AU)

FAPESP's process: 15/25406-5 - Organizing matter: colloids formed by association of surfactants, polymers and nanoparticles
Grantee:Watson Loh
Support Opportunities: Research Projects - Thematic Grants