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VERSION:2.0
PRODID:-//RLASKEY//CALENDEROUS//EN
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METHOD:PUBLISH
BEGIN:VEVENT
DTSTAMP:20260729T213713Z
LAST-MODIFIED:20121116T203436Z
DTSTART:20090731T190000Z
DTEND:20090731T200000Z
UID:event458@bu.edu
URL:http://physics.bu.edu/internal/events/show/458
SUMMARY:Design of Soft Interfaces through Biomimetic Approach
DESCRIPTION:Featuring Atsushi Takahara\, Kyushu University\, Japan\nHosted 
	by: Ophelia Tsui\n\nPart of the Biophysics/Condensed Matter Seminar Series.
	\n\nAbstract:\nSince surfaces and interfaces of soft materials ("soft inter
	face") play an important role in various technological applications and bio
	interfaces\, precise control of soft interfaces would greatly promote the i
	nnovation of future science and technology. In this study\, methods for des
	ign of soft interfaces by biomimetic approach such as nano-texturing of pol
	ymer thin films\, and high-density polymer brush immobilization are present
	ed.\n\nNano-imprinting is a promising method for surface nano-texturing.  T
	he line pattern was imprinted onto poly(fluoroalkyl acrylate) with long cry
	stalline fluoroalkyl group thin film\, and nano-imprinting characteristics 
	of poly(2-pefluorooctylethyl acrylate) (PFA-C8) thin film was investigated.
	  We found out that PFA-C8 could be nano-imprinted even at room temperature
	 because of the weak interaction among fluoroalkyl groups in crystallite at
	 room temperature. The lateral resolution of imprinted pattern was ca.100nm
	. The nano-textured PFA-C8 with orthogonal line patterns exhibited lotus ef
	fect.\n\nSuper hydrophilic polymer brushes were prepared on the silicon waf
	er by surface-initiated atom transfer radical polymerization (ATRP) of 2-me
	thacryloyloxyehtyl phosphorylcholine (MPC) with phosphocholine group. In th
	e case of PMPC\, the swollen brush structure at the water interface was cha
	racterized by neutron reflectivity (NR).  PMPC brush surface showed super h
	ydrophilicity and the air bubble is hardly attached to the PMPC brush surfa
	ce in the hydrated state. The salt concentration dependence of the polymer 
	chain conformation was not observed for PMPC brush because of the net charg
	e of PMPC is negligible. On the other hand\, poly(3-dimethyl(methacryloxyet
	hyl)ammonium propane sulfonate) (PDMAPS) brush exhibited quite different ch
	aracteristics.  Large dependence of the brush thickness on salt concentrati
	on was confirmed by NR and atomic force microscopy (AFM). PDMAPS chains sho
	wed shrunk conformation in pure water due to the strong interchain associat
	ion\, while PDMAPS adopted highly extended chain conformation in a 0.5M NaC
	l solution because salt ions in aqueous solution  screen  the net attractiv
	e electrostatic interaction between PDMAPS chains.\n\n1.K. Honda\, M. Morit
	a\, A. Takahara\, Soft Matter\, 4\,1400-1402 (2008).\n2.M. Kobayashi\, Y. T
	erayama\, M. Kaido\, A. Suzuki\, K. Ishihara\, A. Takahara\, Soft Matter\, 
	3\, 740-746(2007).\n3.Y. Matsuda\, M. Kobayashi\, M. Annaka\, K. Ishihara\,
	 A. Takahara\, Langmuir\, 24\, 8772-8778 (2008).\n4.S.. Horiuchi\, T. Hanad
	a\, M. Ebisawa\, Y. Matsuda\, M. Kobayashi\, A. Takahara\, ACS Nano\, 3\, 1
	297–1304(2009).
LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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