Formation and stability of smooth thin films with soft microgels made of poly(N-isopropylacrylamide) and poly(acrylic acid)

Year: 2020

Authors: Buratti E., Sanzari I., Dinelli F., Prodromakis T., Bertoldo M.

Autors Affiliation: Ist Proc Chim Fis Consiglio Nazl Ric IPCF CNR, Sede Pisa, Via Moruzzi 1, I-56124 Pisa, Italy; Ist Sistemi Complessi Consiglio Nazl Ric ISC CNR, Sede Sapienza, Pz Le Aldo Moro 5, I-00185 Rome, Italy; Univ Southampton, Zepler Inst Photon & Nanoelect, Highfield Campus, Southampton SO17 1BJ, Hants, England; Ist Nazl Ott Consiglio Nazl Ric INO CNR, Via Moruzzi 1, I-56124 Pisa, Italy; Ist Sintesi Organ & Fotoreattivita Consiglio Nazl, Via P Gobetti 101, I-40129 Bologna, Italy; Univ Ferrara, Dipartimento Sci Chim & Farmaceut, Via L Borsari, I-45121 Ferrara, Italy.

Abstract: In this work, soft microgels of Poly(N-Isopropylacrylamide) (PNIPAm) at two different sizes and of interpenetrated polymer network (IPN) composed of PNIPAm and Poly(Acrylic Acid) (PAAc) were synthesized. Then, solutions of these different types of microgels have been spin-coated on glass substrates with different degrees of hydrophobicity. PNIPAm particles with a larger diameter form either patches or a continuous layer, where individual particles are still distinct, depending on the dispersion concentration and spin speed. On the other, PNIPAm particles with a smaller diameter and IPN particles form a continuous and smooth film, with a thickness depending on the dispersion concentration and spin-speed. The difference in morphology observed can be explained if one considers that the microgels may behave as colloidal particles or macromolecules, depending on their size and composition. Additionally, the microgel size and composition can also affect the stability of the depositions when rinsed in water. In particular, we find that the smooth and continuous films show a stimuli-dependent stability on parameters such as temperature and pH, while large particle layers are stable under any condition except on hydrophilic glass by washing at 50 degrees C.

Journal/Review: POLYMERS

Volume: 12 (11)      Pages from: 2638-1  to: 2638-19

More Information: This research was funded by MIUR (Fare project No. R16XLE2X3L, SOFTART) and Norman Godhino Studentship of University of Southampton, UK.
KeyWords: microgels; PNIPAm; PAAc; IPN; thin films; spin-coating
DOI: 10.3390/polym12112638

Citations: 10
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