Formation of a freely suspended membrane via a combination of interfacial reaction and wetting.
Applying poly(ethoxysiloxane) (a liquid non-water-soluble polymer that can be hydrolyzed and cross-linked by diluted acids) to an air/pH 1 water interface gave rise to thin homogeneous solid layers. These layers were strong enough to be transferable to electron microscopy grids with holes of dimensions up to 150 microm and covered the holes as freely suspended membranes. No homogeneous layers were formed at an air/pH 5 water interface. Brewster angle microscopy images show that the poly(ethoxysiloxane) is not spontaneously forming a wetting layer on water. It initially forms lenses, which slowly spread out within several hours. We conclude that the spreading occurs simultaneously with the hydrolysis and cross-linking of the poly(ethoxysiloxane) and that the reaction products finally assist the complete wetting of the water surface.
McNamee
Cathy E
CE
Organic and Macromolecular Chemistry, OC3, The University of Ulm.
Jaumann
Manfred
M
Möller
Martin
M
Ding
Ailin
A
Hemeltjen
Steffen
S
Ebert
Susanne
S
Baumann
Wolfgang
W
Goedel
Werner A
WA