Journal Article

FZJ-2020-01044

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Revealing the Aggregation Mechanism, Structure, and Internal Dynamics of Poly(vinyl alcohol) Microgel Prepared through Liquid–Liquid Phase Separation

Perfetti, M. ; Gallucci, N. ; Russo Krauss, I. ; Radulescu, A.FZJ* ; Pasini, S.FZJ* ; Holderer, O.FZJ* ; D’Errico, G. ; Vitiello, G. ; Bianchetti, G. O. ; Paduano, L. (Corresponding author)

2020
Am. Chem. Soc. Washington, DC

This record in other databases:  

Please use a persistent id in citations: http://hdl.handle.net/2128/24355  doi:10.1021/acs.macromol.9b02203

Abstract: The use of technologies based on soft polymer particles represents an effective way to deliver target molecules with a specific function. To design a well-performing delivery system, it is fundamental to rationalize both the aggregation and the structural properties of such particles. In this study, we present the kinetic and structural characterization over time of poly(vinyl alcohol) (PVA) microgels obtained through a salting-out process in the presence of NaCl. We have analyzed how both the polymer and salt concentrations affect the aggregation process. The aggregation rate as well as the morphology and physico-chemical parameters, such as mass and chain density of the microgels, have been determined through static and dynamic light scattering and discussed in the framework of the diffusion-limited and reaction-limited colloid aggregation. Insights into the polymer chain arrangements and their dynamics have been gained by means of small-angle neutron scattering and neutron spin-echo measurements. As a result, it was found that NaCl induces a liquid phase separation in solution with the formation of spherical PVA microaggregates, which grow under a reaction-limited aggregation mechanism. The particles increase their size and compactness over time. Within the aggregate, the polymer chains are locally organized to form randomly oriented lamellae with a thickness of about 60 Å. The internal dynamics is a complex mixture of diffusion, Zimm dynamics, and possibly effects from crowding with the transition to a Rouse-like behavior. The microparticle preparation based on the salting-out process constitutes a novelty, if compared to the methods already existing and based on the use of chemical cross-linkers, and is a cheap and easy protocol that allows tuning both particle size and density by varying the salt concentration.

Keyword(s): Polymers, Soft Nano Particles and Proteins (1st) ; Soft Condensed Matter (2nd)

---

Contributing Institute(s):

1. JCNS-FRM-II (JCNS-FRM-II)
2. Heinz Maier-Leibnitz Zentrum (MLZ)
3. Neutronenstreuung (JCNS-1)

Research Program(s):

1. 6215 - Soft Matter, Health and Life Sciences (POF3-621) (POF3-621)
2. 6G15 - FRM II / MLZ (POF3-6G15) (POF3-6G15)
3. 6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623) (POF3-623)

Experiment(s):

1. KWS-2: Small angle scattering diffractometer (NL3ao)
2. J-NSE: Neutron spin-echo spectrometer (NL2ao)

Appears in the scientific report 2020

---

Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; IF >= 5 ; JCR ; NCBI Molecular Biology Database ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

---