Suppressing the Hofmeister anion effect by thermal annealing of thin-film multilayers made of weak polyelectrolytes

Klačić, Tin (author), Bohinc, Klemen (author), Kovačević, Davor (author)

Thin films made of weak polyelectrolytes poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) have been fabricated on silicon wafers using the layer-by-layer (LbL) method. To study the influence of counteranion type on the growth and properties of PAH/PAA multilayers, the nature of the supporting sodium salt was varied from cosmotropic to chaotropic anions (F$^–$, Cl$^–$, and ClO$_4$$^–$). Results of ellipsometry and AFM measurements indicate that the film thickness and surface roughness systematically increase on the order F$^–$ < Cl$^–$ < ClO$_4$$^–$. Furthermore, we found that the hydrophobicity of the PAH/PAA multilayer also follows the described trend when a polycation is the terminating layer. However, the heating of PAH/PAA multilayers to 60 °C during the LbL assembly suppressed the influence of background anions on the multilayer formation and properties. On the basis of the obtained results, it could be concluded that thermal annealing induces changes at the polymer–air interface in the sense of reorientation and migration of polymer chains.

• Language: English
• Keywords: layers, polyelectrolytes, surface roughness, thickness, thin films
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: ZF - Faculty of Health Sciences
• Publication status: Published
• Publication version: Version of Record
• Year: 2022
• Number of pages: Str. 9571-9582
• Numbering: Vol. 55, iss. 21
• PID: 20.500.12556/RUL-142605
• UDC: 544.6.018.47-036.5
• ISSN on article: 1520-5835
• DOI: 10.1021/acs.macromol.2c01517
• COBISS.SI-ID: 129267715
• Publication date in RUL: 15.11.2022

Record is a part of a journal

• Title: Macromolecules
• Shortened title: Macromolecules
• Publisher: American Chemical Society
• ISSN: 1520-5835
• COBISS.SI-ID: 512807449

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: plasti, polielektroliti, površinska hrapavost, debelina, tanki sloji