Reversible Size Modulation of Aqueous Microgels via Orthogonal or Combined Application of Thermo- and Phototriggers

Aqueous microgels that respond orthogonally to external temperature and light stimuli and to a combination of both stimuli were developed. N-Vinylcaprolactam (VCL) was copolymerized with small feed amounts (<5 mol %) of 4-[(4-methacryloyloxy)phenylazo] benzenesulfonic acid (ABSA) and cross-linked...

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Veröffentlicht in:Langmuir : the ACS journal of surfaces and colloids. - 1992. - 32(2016), 16 vom: 26. Apr., Seite 3867-79
1. Verfasser: Phua, Dazril I (VerfasserIn)
Weitere Verfasser: Herman, Krisztian, Balaceanu, Andreea, Zakrevski, Juri, Pich, Andrij
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2016
Zugriff auf das übergeordnete Werk:Langmuir : the ACS journal of surfaces and colloids
Schlagworte:Journal Article Research Support, Non-U.S. Gov't
Beschreibung
Zusammenfassung:Aqueous microgels that respond orthogonally to external temperature and light stimuli and to a combination of both stimuli were developed. N-Vinylcaprolactam (VCL) was copolymerized with small feed amounts (<5 mol %) of 4-[(4-methacryloyloxy)phenylazo] benzenesulfonic acid (ABSA) and cross-linked with N,N'-methylenebis(acrylamide) (BIS) to synthesize monodisperse and colloidally stable P(VCL-BIS-ABSA) microgels. The volume phase transition information on the microgels under both orthogonal and combined application of temperature and light stimuli was investigated in situ by dynamic light scattering (DLS) instrument. Modeling of this information by the Flory-Rehner theory describes and aids the preliminary understanding of the main features in the volume phase transition of these photoresponsive microgels. Interestingly, the microgels rapidly deswell upon UV irradiation (λ = 365 nm), even as the trans-ABSA pendant groups are converted to the more polar cis state. The variation in the content of the pendant azobenzene groups in the microgels allows for reversible modulation of the phototriggered volume change. We propose that the approach of the sulfonic acid groups of cis-ABSA toward the polymer backbone causes the disruption of hydrogen bonding interactions between water molecules and the carbonyl groups of VCL
Beschreibung:Date Completed 18.05.2018
Date Revised 18.05.2018
published: Print-Electronic
Citation Status PubMed-not-MEDLINE
ISSN:1520-5827
DOI:10.1021/acs.langmuir.6b00241