Engineering Surface Hydrophilicity via Polymer Chain-End Segregation in Coatings Formed by Photopolymerization

Caroline Rose Szczepanski*, John M. Torkelson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

The manipulation of surface chemistry, and more precisely the hydrophilic/hydrophobic nature of an interfacial material, is essential for many applications in coatings, biomaterials, and microfluidics. To engineer surface hydrophobicity, prior research has relied heavily on the segregation of low surface energy compounds, e.g., fluorinated alcohols or polymers, toward a free surface, thus increasing the surface hydrophobicity. While this approach is effective in creating hydrophobic interfaces, many applications in water harvesting and guidance require hydrophilic surface chemistries. Currently, many researchers utilize secondary postfunctionalization to integrate hydrophilic moieties at a surface, which typically requires additional precursors and reagents. Here, we demonstrate that the chain-end units of low-molecular-weight polystyrene additives can be exploited to promote segregation of hydrophilic moieties toward a free surface during network cure, thus increasing the wettability of polymeric surfaces in a single polymerization procedure. The efficacy of this approach depends on two factors: (1) the time available prior to vitrification and restriction of chain-end segregation and (2) the molecular weight of the polystyrene additive employed. We demonstrate that ambient photopolymerization provides a versatile, tailorable platform for manipulating the time available for chain-end segregation prior to vitrification. Our approach provides a framework from which hydrophilic surface chemistry can be easily engineered and patterned in rigid, cross-linked coatings without the use of secondary functionalization procedures.

Original languageEnglish (US)
Pages (from-to)3095-3102
Number of pages8
JournalACS Applied Polymer Materials
Volume1
Issue number11
DOIs
StatePublished - Nov 8 2019

Funding

This work made use of the Keck-II facility of Northwestern University’s NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN.

Keywords

  • chain-end
  • hydrophilicity
  • low-molecular-weight polymers
  • photopolymerization
  • surface wettability

ASJC Scopus subject areas

  • Polymers and Plastics
  • Process Chemistry and Technology
  • Organic Chemistry

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