Photocrosslinkable Polymeric Bicontinuous Microemulsions

Michael B Sims, Joshua W. Goetze, Gabriela Diaz Gorbea, Zachary M Gdowski, Timothy P. Lodge, Frank S Bates

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

We present an approach to photocrosslink bicontinuous microemulsions derived from ternary blends of poly(methoxyethyl acrylate) (PM, Mn = 4200 g/mol), poly(hexyl methacrylate-co-coumarin methacrylate) (PHC, Mn = 6800 g/mol), and PM-b-PHC diblock polymer (Mn = 19,400 g/mol) in a phase-selective manner, enabling structural characterization at an unprecedented level of detail. This strategy utilizes the [2 + 2] photodimerization reaction of coumarin derivatives to covalently crosslink blends without the use of harsh reagents or disruptive thermal treatment, thus preserving the intricate network structure throughout curing. The resulting crosslinked bicontinuous microemulsions exhibited rubbery behavior at elevated temperatures, achieving an elastic shear modulus of nearly 1 MPa at 70 °C, owing to the presence of the three-dimensional co-continuous network morphology. The dimensional stabilization afforded by crosslinking further allowed the microstructure to be directly imaged by scanning electron microscopy and atomic force microscopy. Contrary to recent theoretical findings, the BμE appears in a wide temperature and compositional window, suggesting that it is a robust feature of these blends. As a proof of concept demonstrating both the utility of bicontinuous microemulsion-derived materials and versatility of this strategy toward broader applications in energy storage and transport, the uncrosslinked portion of a cured blend was extracted by washing and replaced with an ionic liquid; the resultant heterogeneous solid electrolyte exhibited a room-temperature conductivity of 2 mS/cm, approximately one-quarter that of the pure ionic liquid.

Bibliographical note

Funding Information:
This work was supported by the Office of Basic Energy Sciences (BES) of the U.S. Department of Energy (DoE) under Contract DE-SC0017809. SAXS, SEM, and AFM were carried out in the Characterization Facility, University of Minnesota, which receives partial support from the National Science Foundation MRSEC (DMR-2011401) and NNCI (ECCS-2025124) programs. Joanna White and Stephanie Liffland are gratefully acknowledged for their assistance in performing synchrotron X-ray scattering experiments.

Publisher Copyright:
© 2023 American Chemical Society.

Keywords

  • bicontinuous microemulsion
  • coumarin
  • diblock polymers
  • microphase separation
  • nanoporous materials
  • photocrosslinking
  • polymer blends

MRSEC Support

  • Shared

PubMed: MeSH publication types

  • Journal Article

Fingerprint

Dive into the research topics of 'Photocrosslinkable Polymeric Bicontinuous Microemulsions'. Together they form a unique fingerprint.

Cite this