skip to main content

DOE PAGESDOE PAGES

This content will become publicly available on September 6, 2019

Title: Reversible hierarchical structure induced by solvation and temperature modulation in an ionic liquid-based random bottlebrush copolymer

Here a solvent and temperature responsive random copolymer having a polyacrylate backbone with emanating ionic liquid side chains of 1-decyl-3-methylimidazolium chloride and 1-(2-carboxyethyl)-3-imidazolium bromide grafted poly-N-isopropylacrylamide (PNIPAM) possessing bottlebrush architecture is synthesized. The bottlebrush copolymer is prepared using an uncommon route that exploits the co-assembly of two amphiphilic ionic liquid acryloyl-based monomers in 30% (w/w) water to form a lyotropic mesophase followed by photo-initiated free radical polymerization. The copolymer adopts a temperature-invariant 2D hexagonal structure as determined by SAXS in the dehydrated (de-swollen) state. The absence of thermoresponsivity is attributed to a combination of confinement coupled with insufficient solvation of the grafted PNIPAM chains. In a water-swollen state (hydrogel), loss in long range translational ordering is observed while short range temperature-dependent ordering dominates. Below the LCST of PNIPAM (<40 °C), disassociated nanoscale discoidal assemblies predominate, as determined by SAXS. At temperatures above the LCST, the particles condense to form thicker circular discs of similar diameter. Polarized optical microscopy shows the formation of 1-D liquid-crystalline fibrillar structures spanning the meso- to micro-length scales. The assembly and disassembly are fully reversible with temperature cycling. Finally, this work demonstrates the possibility of achieving self-organization over multiple length scales (panoscopic) to create complex structuresmore » from modular components using an external stimulus to control construction.« less
Authors:
 [1] ; ORCiD logo [1] ;  [2] ; ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Argonne National Lab. (ANL), Argonne, IL (United States). X-ray Sciences Division
Publication Date:
Report Number(s):
LA-UR-18-28367
Journal ID: ISSN 1759-9954
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Polymer Chemistry
Additional Journal Information:
Journal Volume: 9; Journal Issue: 42; Journal ID: ISSN 1759-9954
Publisher:
Royal Society of Chemistry
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1482012

Magurudeniya, Harsha D., Ringstrand, Bryan S., Seifert, Sönke, and Firestone, Millicent A.. Reversible hierarchical structure induced by solvation and temperature modulation in an ionic liquid-based random bottlebrush copolymer. United States: N. p., Web. doi:10.1039/C8PY01218K.
Magurudeniya, Harsha D., Ringstrand, Bryan S., Seifert, Sönke, & Firestone, Millicent A.. Reversible hierarchical structure induced by solvation and temperature modulation in an ionic liquid-based random bottlebrush copolymer. United States. doi:10.1039/C8PY01218K.
Magurudeniya, Harsha D., Ringstrand, Bryan S., Seifert, Sönke, and Firestone, Millicent A.. 2018. "Reversible hierarchical structure induced by solvation and temperature modulation in an ionic liquid-based random bottlebrush copolymer". United States. doi:10.1039/C8PY01218K.
@article{osti_1482012,
title = {Reversible hierarchical structure induced by solvation and temperature modulation in an ionic liquid-based random bottlebrush copolymer},
author = {Magurudeniya, Harsha D. and Ringstrand, Bryan S. and Seifert, Sönke and Firestone, Millicent A.},
abstractNote = {Here a solvent and temperature responsive random copolymer having a polyacrylate backbone with emanating ionic liquid side chains of 1-decyl-3-methylimidazolium chloride and 1-(2-carboxyethyl)-3-imidazolium bromide grafted poly-N-isopropylacrylamide (PNIPAM) possessing bottlebrush architecture is synthesized. The bottlebrush copolymer is prepared using an uncommon route that exploits the co-assembly of two amphiphilic ionic liquid acryloyl-based monomers in 30% (w/w) water to form a lyotropic mesophase followed by photo-initiated free radical polymerization. The copolymer adopts a temperature-invariant 2D hexagonal structure as determined by SAXS in the dehydrated (de-swollen) state. The absence of thermoresponsivity is attributed to a combination of confinement coupled with insufficient solvation of the grafted PNIPAM chains. In a water-swollen state (hydrogel), loss in long range translational ordering is observed while short range temperature-dependent ordering dominates. Below the LCST of PNIPAM (<40 °C), disassociated nanoscale discoidal assemblies predominate, as determined by SAXS. At temperatures above the LCST, the particles condense to form thicker circular discs of similar diameter. Polarized optical microscopy shows the formation of 1-D liquid-crystalline fibrillar structures spanning the meso- to micro-length scales. The assembly and disassembly are fully reversible with temperature cycling. Finally, this work demonstrates the possibility of achieving self-organization over multiple length scales (panoscopic) to create complex structures from modular components using an external stimulus to control construction.},
doi = {10.1039/C8PY01218K},
journal = {Polymer Chemistry},
number = 42,
volume = 9,
place = {United States},
year = {2018},
month = {9}
}

Works referenced in this record:

Reduction and analysis of SANS and USANS data using IGOR Pro
journal, November 2006