このエントリーをはてなブックマークに追加
ID 60247
FullText URL
Author
Watanabe, Takaichi Department of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University ORCID Kaken ID researchmap
Lopez, Carlos G. Department of Chemical Engineering, Imperial College London
Douglas, Jack F. Materials Science and Engineering Division, National Institute of Standards and Technology
Ono, Tsutomu Department of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University ORCID Kaken ID publons researchmap
Cabral, João T. Department of Chemical Engineering, Imperial College London
Abstract
We report the controlled formation of internally porous polyelectrolyte particles with diameters ranging from tens to hundreds of micrometers through selective solvent extraction using microfluidics. Solvent-resistant microdevices, fabricated by frontal photopolymerization, encapsulate binary polymer (P)/solvent (S1) mixtures by a carrier solvent phase (C) to form plugs with well-defined radii and low polydispersity; the suspension is then brought into contact with a selective extraction solvent (S2) that is miscible with C and S1 but not P, leading to the extraction of S1 from the droplets. The ensuing phase inversion yields polymer capsules with a smooth surface but highly porous internal structure. Depending on the liquid extraction time scale, this stage can be carried out in situ, within the chip, or ex situ, in an external S2 bath. Bimodal polymer plugs are achieved using asymmetrically inverted T junctions. For this demonstration, we form sodium poly(styrenesulfonate) (P) particles using water (S1), hexadecane (C), and methyl ethyl ketone (S2). We measure droplet extraction rates as a function of drop size and polymer concentration and propose a simple scaling model to guide particle formation. We find that the extraction time required to form particles from liquid droplets does not depend on the initial polymer concentration but is rather proportional to the initial droplet size. The resulting particle size follows a linear relationship with the initial droplet size for all polymer concentrations, allowing for the precise control of particle size. The internal particle porous structure exhibits a polymer density gradient ranging from a dense surface skin toward an essentially hollow core. Average particle porosities between 10 and 50% are achieved by varying the initial droplet compositions up to 15 wt % polymer. Such particles have potential applications in functional, optical, and coating materials.
Published Date
2014-02-9
Publication Title
Langmuir
Volume
volume30
Issue
issue9
Publisher
American Chemical Society
Start Page
2470
End Page
2479
ISSN
0743-7463
NCID
AA10461730
Content Type
Journal Article
language
英語
OAI-PMH Set
岡山大学
File Version
author
PubMed ID
DOI
Web of Science KeyUT
Related Url
isVersionOf https://doi.org/10.1021/la404506b