New strategy to create ultra-thin surface layer of grafted amphiphilic macromolecules
AA Lazutin and EN Govorun and VV Vasilevskaya and AR Khokhlov, JOURNAL OF CHEMICAL PHYSICS, 142, 184904 (2015).
It was found first that macromolecules made of amphiphilic monomer units could form spontaneously an ultra-thin layer on the surface which the macromolecules are grafted to. The width of such layer is about double size of monomer unit consisting of hydrophilic A (repulsive) and hydrophobic (attractive) B beads. The hydrophilic A beads are connected in a polymer chain while hydrophobic B beads are attached to A beads of the backbone as side groups. Three characteristic regimes are distinguished. At low grafting density, the macromolecules form ultra- thin micelles of the shape changing with decrease of distance d between grafting points as following: circular micelles-prolonged micelles- inverse micelles-homogeneous bilayer. Those micelles have approximately constant height and specific top-down A-BB-A structure. At higher grafting density, the micelles start to appear above the single bilayer of amphiphilic macromolecules. The thickness of grafted layer in these cases is different in different regions of grafting surface. Only at rather high density of grafting, the height of macromolecular layer becomes uniform over the whole grafting surface. The study was performed by computer modeling experiments and confirmed in framework of analytical theory. (C) 2015 AIP Publishing LLC.
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