Solid-state polymer adsorption for surface modification: The role of molecular weight

Hypothesis: Solid-state polymer adsorption offers a distinct approach for surface modification. These ultrathin, so-called Guiselin layers can easily be obtained by placing a polymer melt in contact with an interface, followed by a removal of the non-adsorbed layer with a good solvent. While the mechanism of formation has been well established for Guiselin layers, their stability, crucial from the perspective of materials applications, is not. The stability is a trade-off in the entropic penalty between cooperative detachment of the number of segments directly adsorbed on the substrate and consecutively pinned monomers. Experiments: Experimental model systems of Guiselin layers of polystyrene (PS) on silicon wafers with native oxide layer on top were employed. The stability of the adsorbed layers was studied as a function of PS molecular weight and polydispersibility by various microscopic and spectroscopic tools as well as quasi-static contact angle measurements. Findings: Adsorbed layers from low molecular weight PS were disrupted with typical spinodal decomposition patterns whereas high molecular weight (>500 kDa) PS resulted in stable, continuous layers. Moreover, we show that Guiselin layers offer an enticing way to modify a surface, as demonstrated by adsorbed PS that imparts a hydrophobic character to initially hydrophilic silicon wafers.

Description

Funding Information: W.X. acknowledges the funding from Tandem Forest Values (Project STRONGAD). Prof. Pekka Peljo is thanked for helping with contact angle measurements. Olle Engkvists Stiftelse (Sweden) is acknowledged for funding the nano infrared microscope as well as a postdoc scholarship for K.N. Dr. Leena-Sisko Johansson is thanked for assisting with XPS analyses and data interpretation. Dr. Katja Heise is thanked for helping with GPC measurements. Dr. Zhuojun Meng and Tao Zou (M.Sc.) are thanked for valuable discussions. This work made use of Aalto University Bioeconomy and RawMatters Facilities. We also acknowledge the provision of facilities and technical support by Aalto University at OtaNano - Nanomicroscopy Center (Aalto-NMC). The study is a part of FinnCERES Materials Bioeconomy Ecosystem. Funding Information: W.X. acknowledges the funding from Tandem Forest Values (Project STRONGAD). Prof. Pekka Peljo is thanked for helping with contact angle measurements. Olle Engkvists Stiftelse (Sweden)is acknowledged for funding the nano infrared microscope as well as a postdoc scholarship for K.N. Dr. Leena-Sisko Johansson is thanked for assisting with XPS analyses and data interpretation. Dr. Katja Heise is thanked for helping with GPC measurements. Dr. Zhuojun Meng and Tao Zou (M.Sc.) are thanked for valuable discussions. This work made use of Aalto University Bioeconomy and RawMatters Facilities. We also acknowledge the provision of facilities and technical support by Aalto University at OtaNano - Nanomicroscopy Center (Aalto-NMC). The study is a part of FinnCERES Materials Bioeconomy Ecosystem. Publisher Copyright: © 2021 The Author(s)

Keywords

Contact angle, Dewetting, Polymer adsorption, Polystyrene, Silicon wafers, Surface modification

DOI

10.1016/j.jcis.2021.07.062

Citation

Xu , W , Mihhels , K , Kotov , N , Lepikko , S , Ras , R H A , Johnson , C M , Pettersson , T & Kontturi , E 2022 , ' Solid-state polymer adsorption for surface modification: The role of molecular weight ' , Journal of Colloid and Interface Science , vol. 605 , pp. 441-450 . https://doi.org/10.1016/j.jcis.2021.07.062

Permanent link to this item

https://urn.fi/URN:NBN:fi:aalto-202108258446

Collections

[article-cris] Kemian tekniikan korkeakoulu / CHEM

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