Langmuir, 24 (6), 2446 -2451, 2008. 10.1021/la703546f S0743-7463(70)03546-1
Web Release Date: February 8, 2008

Copyright © 2008 American Chemical Society

Production of Uniform-Sized Polymer Core-Shell Microcapsules by Coaxial Electrospraying

Yoon Kyun Hwang, Unyong Jeong,* and Eun Chul Cho

Department of Materials Science and Engineering, Yonsei University, 134 Shinchon-dong, Seoul 120-749, Korea and Amorepacific Corporation/R&D Center, 314-1, Bora-dong, Yong-in City, 449-729, Korea 1700

Received November 13, 2007

In Final Form: December 10, 2007

Abstract:

Spherical polymeric core-shell microcapsules in uniform size were produced by electrospraying with a coaxial nozzle setup. Contrary to the usual coaxial setup, the inner nozzle was slightly bent to touch the inside wall of the outer nozzle. A polymer solution for the core was introduced through the outer nozzle, and the other solution for the shell was supplied through the inner nozzle. The setup greatly increased reproduction of the same results. As a proof of the concept, core-shell microcapsules consisting of a PS or PMMA core and a PCL shell (PS@PCL, PMMA@PCL) were produced. When the volumetric feed rate of the shell-forming PCL solution was higher than that of the core-forming PS or PMMA solution the core-shell structures in uniform size were readily obtained. In contrast, irregular morphologies were observed when the feed rate of the PCL solution was slower or equal to that of the PS or PMMA solution. The size of the colloid was dependent on the relative feed ratio between the polymer solutions as well as the magnitude of applied voltage.


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