Multilayered Polymer Microspheres by Thermal Imprinting during Microsphere Growth
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- 作者：Ryu Takekoh ; Wen-Hui Li ; Nicholas A. D. Burke ; and Harald D. H. Stö ; ver
- 刊名：Journal of the American Chemical Society
- 出版年：2006
- 出版时间：January 11, 2006
- 年：2006
- 卷：128
- 期：1
- 页码：240 - 244
- 全文大小：653K
- 年卷期：v.128,no.1(January 11, 2006)
- ISSN：1520-5126
文摘
Modulation of the polymerization temperature in precipitation polymerizations was used to formonion-type polymer microspheres consisting of multiple nested layers. Specifically, the copolymerizationof chloromethylstyrene and divinylbenzene-55 in acetonitrile, at temperatures ramping between 65 and 75
C, led to monodisperse, cross-linked microspheres of about 10 
m diameter that have radial density profilesclosely reflecting the thermal profiles used. This thermal imprinting is attributed to the copolymer formedbeing close to its theta point during the polymerization. As the microspheres grow by continuously capturingoligomers from solution, the resulting transient surface gel layer expands and contracts with temperature,and thus records the reaction temperature profile in the form of a corresponding density profile, even as itcross-links.
C, led to monodisperse, cross-linked microspheres of about 10 m diameter that have radial density profilesclosely reflecting the thermal profiles used. This thermal imprinting is attributed to the copolymer formedbeing close to its theta point during the polymerization. As the microspheres grow by continuously capturingoligomers from solution, the resulting transient surface gel layer expands and contracts with temperature,and thus records the reaction temperature profile in the form of a corresponding density profile, even as itcross-links.