The Role of Light Irradiation and Dendrimer Generation in Directing Electrostatic Self-Assembly

Agarwal M, Zika A, Yücel M, Schweins R, Kohlbrecher J, Gröhn F (2025)

Publication Type: Journal article

Publication year: 2025

Journal

Polymers MDPI

Book Volume: 17

Article Number: 170

Journal Issue: 2

DOI: 10.3390/polym17020170

Abstract

pH-responsive polyamidoamine (PAMAM) dendrimers are used as well-defined building blocks to design light-switchable nano-assemblies in solution. The complex interplay between the photoresponsive di-anionic azo dye Acid Yellow 38 (AY38) and the cationic PAMAM dendrimers of different generations is presented in this study. Electrostatic self-assembly involving secondary dipole–dipole interactions provides well-defined assemblies within a broad size range (10 nm–1 μm) with various shapes. The size and shape of these assemblies were determined using dynamic and static light scattering (DLS/SLS) and small-angle neutron scattering (SANS); ζ-potential measurements were performed to elucidate the charge characteristics, revealing the effective surface charge density of the nano-objects as an important parameter in the size and shape control. UV–vis spectroscopy and isothermal titration calorimetry (ITC) were employed to investigate the interaction on a molecular level and from a thermodynamic point of view. The results show that the amount of isomerized cis dye depends on the dendrimer generation because of a photoprotective effect through electrostatics for lower generations and through dipole–dipole interactions for higher generations; as the cis dye and trans dye bind with different strength, the amount of cis dye then again encodes the charge density and thereby the particle size and shape.

Authors with CRIS profile

Mohit Agarwal Interdisziplinäres Zentrum für Molekulare Materialien (ICMM) Alexander Zika Professur für Molekulare Nanostrukturen Müge Yücel Lehrstuhl für Physikalische Chemie I Franziska Gröhn Professur für Molekulare Nanostrukturen

Involved external institutions

Institute Laue-Langevin (ILL) FR France (FR) Paul Scherrer Institute (PSI) CH Switzerland (CH)

How to cite

APA:

Agarwal, M., Zika, A., Yücel, M., Schweins, R., Kohlbrecher, J., & Gröhn, F. (2025). The Role of Light Irradiation and Dendrimer Generation in Directing Electrostatic Self-Assembly. Polymers, 17(2). https://doi.org/10.3390/polym17020170

MLA:

Agarwal, Mohit, et al. "The Role of Light Irradiation and Dendrimer Generation in Directing Electrostatic Self-Assembly." Polymers 17.2 (2025).

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