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Title: Synthetic control of the size, shape, and polydispersity of anisotropic silica colloids

The particle size and shape determine the microstructure and rheological properties of colloidal suspensions. This work aims to further control the size, shape, and polydispersity of anisotropic silica colloids, to reduce particle size, and to provide additional mechanistic insights on a prevalent, water-in-oil emulsion synthesis method. Key findings show that the dimensions of anisotropic silica particles can be systematically varied by approximately fivefold, with a limiting minimum particle size (D ≈ 60 nm, L ≈ 300 nm) obtained from emulsions with excess polyvinylpyrrolidone (PVP) and sodium citrate. The synthesis conditions are identified and discussed for which the emulsion composition, temperature, sonication, polymer entanglements, mixing, and other perturbations may induce or mitigate emulsion instabilities, citrate precipitation, a competing mechanism of templated growth, termination of anisotropic growth, irregular silica structures, and fiber formation. An improved mechanistic understanding will expand the roadmap for rational design and synthetic control of anisotropic colloids using sol-gel silica chemistry confined within water-in-oil emulsions.
Authors:
 [1] ;  [2] ;  [1]
  1. Univ. of Delaware, Newark, DE (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725; AC02-06CH11357
Type:
Publisher's Accepted Manuscript
Journal Name:
Journal of Colloid and Interface Science
Additional Journal Information:
Journal Volume: 501; Journal ID: ISSN 0021-9797
Publisher:
Elsevier
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1414796
Alternate Identifier(s):
OSTI ID: 1361329