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Controlling Nanoparticle Location via Confined Assembly in Electrospun Block Copolymer Nanofibers
Author(s) -
Kalra Vibha,
Lee Jinwoo,
Lee Jung Hun,
Lee Seung Goo,
Marquez Manuel,
Wiesner Ulrich,
Joo Yong Lak
Publication year - 2008
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.200800279
Subject(s) - materials science , nanoparticle , nanofiber , nanocomposite , copolymer , superparamagnetism , chemical engineering , electrospinning , nanoporous , transmission electron microscopy , dispersity , lamellar structure , nanotechnology , polymer chemistry , composite material , polymer , magnetization , physics , quantum mechanics , magnetic field , engineering
Coaxial nanofibers with poly(styrene‐ block‐ isoprene) (PS‐ b‐ PI)/magnetite nanoparticles as core and silica as shell are fabricated using electrospinning.1–4 Thermally stable silica helps to anneal the fibers above the glass transition temperature of PS‐ b‐ PI and form ordered nanocomposite morphologies. Monodisperse magnetite nanoparticles (NPs; 4 nm) are synthesized and surface coated with oleic acid to provide marginal selectivity towards an isoprene domain. When 4 wt% nanoparticles are added to symmetric PS‐ b ‐PI, transmission electron microscopy (TEM) images of microtomed electrospun fibers reveal that NPs are uniformly dispersed only in the PI domain, and that the confined lamellar assembly in the form of alternate concentric rings of PS and PI is preserved. For 10 wt% NPs, a morphology transition is seen from concentric rings to a co‐continuous phase with NPs again uniformly dispersed in the PI domains. No aggregates or loss of PI selectivity is found in spite of interparticle attraction. Magnetic properties are measured using a superconducting quantum interference device (SQUID) magnetometer and all nanocomposite fiber samples exhibit superparamagnetic behavior.