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pH dependent polymeric micelle adsorption

Abstract

Full text: Poly(2-vinylpyridine)-poly(ethylene oxide) (P2VP-PEO) shows potential as a possible drug delivery system for anti-tumour drugs since it forms pH dependent polymeric micelles. Hence to better understand the adsorption behaviour of this polymer we have studied the interaction forces between layers of P2VP-PEO adsorbed onto silica as a function of solution pH using an Atomic Force Microscope (AFM). When P2VP-PEO is initially adsorbed above the pKa of the P2VP block, P2VP-PEO adsorbs from solution as micelles that exist as either partially collapsed- or a hemi-micelles at the silica surface. Below the pKa of P2VP, the P2VP-PEO adsorbs as unimers, forming a compact layer with little looping and tailing into solution. When initial adsorption of P2VP-PEO is in the form of unimers, any driving force to self-assembly of the now charge neutral polymer is kinetically hindered. Hence, after initial adsorption at pH 3.6, a subsequent increase in pH to 6.6 results in a slow surface restructuring towards self-assembly and equilibrium. When the pH is increased from pH 6.6 to 9.7 there is a continuation of the evolution of the system to its equilibrium position during which the adsorbed P2VP-PEO unimers continue to 'unravel' from the surface, extending away from it, towards  More>>
Authors:
McLean, S C; Gee, M L [1] 
  1. The University of Melbourne, VIC (Australia). School of Chemistry
Publication Date:
Jul 01, 2003
Product Type:
Conference
Resource Relation:
Conference: 2. AINSE Symposium on Small-Angle Scattering and Reflectometry, Lucas Heights, NSW (Australia), 25-26 Jun 2003; Other Information: PBD: 2003; Related Information: In: 2nd AINSE Symposium on Small-Angle Scattering and Reflectometry. Program and Abstracts, 54 pages.
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ADSORPTION; ATOMIC FORCE MICROSCOPY; DRUGS; MICELLAR SYSTEMS; PH VALUE; POLYETHYLENES; POLYVINYLS; PYRIDINIUM COMPOUNDS; SILICON OXIDES
OSTI ID:
20461304
Research Organizations:
Australian Institute of Nuclear Science and Engineering, Lucas Heights, NSW (Australia)
Country of Origin:
Australia
Language:
English
Other Identifying Numbers:
TRN: AU0423107038119
Availability:
Available in abstract form only, full text entered in this record
Submitting Site:
INIS
Size:
page(s) 44
Announcement Date:
May 31, 2004

Citation Formats

McLean, S C, and Gee, M L. pH dependent polymeric micelle adsorption. Australia: N. p., 2003. Web.
McLean, S C, & Gee, M L. pH dependent polymeric micelle adsorption. Australia.
McLean, S C, and Gee, M L. 2003. "pH dependent polymeric micelle adsorption." Australia.
@misc{etde_20461304,
title = {pH dependent polymeric micelle adsorption}
author = {McLean, S C, and Gee, M L}
abstractNote = {Full text: Poly(2-vinylpyridine)-poly(ethylene oxide) (P2VP-PEO) shows potential as a possible drug delivery system for anti-tumour drugs since it forms pH dependent polymeric micelles. Hence to better understand the adsorption behaviour of this polymer we have studied the interaction forces between layers of P2VP-PEO adsorbed onto silica as a function of solution pH using an Atomic Force Microscope (AFM). When P2VP-PEO is initially adsorbed above the pKa of the P2VP block, P2VP-PEO adsorbs from solution as micelles that exist as either partially collapsed- or a hemi-micelles at the silica surface. Below the pKa of P2VP, the P2VP-PEO adsorbs as unimers, forming a compact layer with little looping and tailing into solution. When initial adsorption of P2VP-PEO is in the form of unimers, any driving force to self-assembly of the now charge neutral polymer is kinetically hindered. Hence, after initial adsorption at pH 3.6, a subsequent increase in pH to 6.6 results in a slow surface restructuring towards self-assembly and equilibrium. When the pH is increased from pH 6.6 to 9.7 there is a continuation of the evolution of the system to its equilibrium position during which the adsorbed P2VP-PEO unimers continue to 'unravel' from the surface, extending away from it, towards eventual complete surface self-assembly.}
place = {Australia}
year = {2003}
month = {Jul}
}