Microfluidic preparation of dual stimuli-responsive microparticles and light-directed clustering

Saifullah Lone, Sung Hoon Kim, Seong Won Nam, Sungsu Park, In Woo Cheong

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

We present a simple fabrication of photo- and thermoresponsive microparticles with a narrow size distribution in the PDMS-based microfluidic device. The monodisperse water-in-oil (W/O) droplets of poly(N- isopropylacrylamide-co-spironaphthoxazine methacryloyl) (PNIPA-SPO) were formed at the T-junction channel of the device by adjusting the flow conditions of two immiscible solutions. Subsequently, the droplets were polymerized downstream of the channel under 365 nm UV irradiation in the presence of 2,2′- diethoxyacetophenone (DEAP, photoinitiator) and N,N′- methylenebisacrylamide (MBA, monomer and cross-linker). Being photosensitive, the polymerized microparticles progressively change their color when subjected to UV-vis irradiation. Above the LCST of the copolymer, the microparticles exhibited volume shrinkage accompanied by color deterioration. In addition, the UV light-driven clustering of the PNIPA-SPO copolymer was observed within the W/O droplet in the absence of photoinitiator, which contributed to variable microstructures from Janus to acorn-like and snowman-like morphologies. This work is the first attempt to unveil the photocontrolled asymmetric particle morphology by using the photoresponsive polymer.

Original languageEnglish
Pages (from-to)17975-17980
Number of pages6
JournalLangmuir
Volume26
Issue number23
DOIs
StatePublished - 7 Dec 2010

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