Spinning a Yarn Ball

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Science  15 Dec 2000:
Vol. 290, Issue 5499, pp. 2035
DOI: 10.1126/science.290.5499.2035b

One approach for directing polymer morphology is to use a microporous template to control polymerization reactions. Kossyrev and Crawford used an alumina membrane with cylindrical pores (0.2 micrometer in diameter) and coated the interior of these pores with a liquid crystalline monomer before triggering photopolymerization. Hollow tubes formed within untreated pores, but pretreating the pores with lecithin resulted in the formation of polymer threads. When these threads are released by etching away the alumina, the polymer skin shrinks, and the intrinsically straight thread collapses into a tightly packed “yarn ball” configuration. Because of the alignment of the polymer within the thread, application of an electric field (5 to 10 volts per micrometer) reverses the structural collapse and converts the yarn ball back into an untangled thread. — PDS

Appl. Phys. Lett.77, 3752 (2000).

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