Controlling Anti-Penetration Performance by Post-Grafting of Fluorinated Alkyl Chains onto Polystyrene- block-poly(vinyl methyl siloxane)

Zhenglin Zhang; Krishnaroop Chaudhuri; Florian Kaefer; Anthony P Malanoski; Kirt A Page; Louisa M Smieska; Jonathan T Pham; Christopher K Ober

doi:10.1021/acsami.4c01905

Controlling Anti-Penetration Performance by Post-Grafting of Fluorinated Alkyl Chains onto Polystyrene- block-poly(vinyl methyl siloxane)

ACS Appl Mater Interfaces. 2024 Apr 17;16(15):19594-19604. doi: 10.1021/acsami.4c01905. Epub 2024 Apr 8.

Authors

Zhenglin Zhang¹, Krishnaroop Chaudhuri², Florian Kaefer¹, Anthony P Malanoski³, Kirt A Page^{4

5

6}, Louisa M Smieska⁴, Jonathan T Pham², Christopher K Ober¹

Affiliations

¹ Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States.
² Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, Ohio 45221, United States.
³ United States Naval Research Laboratory, Center for Biomolecular Science and Engineering, Washington, District of Columbia 20375, United States.
⁴ Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, New York 14853, United States.
⁵ Materials and Manufacturing Directorate, Air Force Research Laboratory, WPAFB, Dayton, Ohio 45433, United States.
⁶ UES Inc., Dayton, Ohio 45432, United States.

PMID: 38588386
DOI: 10.1021/acsami.4c01905

Abstract

Polydimethylsiloxane (PDMS) has been widely used as a surface coating material, which has been reported to possess dynamic omniphobicity to a wide range of both polar and nonpolar solvents due to its high segmental flexibility and mobility. However, such high flexibility and mobility also enable penetration of small molecules into PDMS coatings, which alter the chemical and physical properties of the coating layers. To improve the anti-penetration properties of PDMS, a series of fluorinated alkyl segments are grafted to a diblock copolymer of polystyrene-block-poly(vinyl methyl siloxane) (PS-b-PVMS) using thiol-ene click reactions. This article reports the chemical characterization of these model fluorosilicone block copolymers and uses fluorescence measurements to investigate the dye penetration characteristics of polymer thin films. The introduction of longer fluorinated alkyl chains can gradually increase the anti-penetration properties as the time to reach the maximum fluorescence intensity (t_peak) gradually increases from 11 s of PS-b-PVMS to more than 1000 s of PS-b-P(n-C₆F₁₃-VMS). The improvement of anti-penetration properties is attributed to stronger inter-/intrachain interactions, phase segregation of ordered fluorinated side chains, and enhanced hydrophobicity caused by the grafting of fluorinated alkyl chains.

Keywords: antipenetration; coating; fluorination; in situ fluorescence; polydimethylsiloxane.