Telechelic poly(ethylene oxide) amphiphiles with polyhedral oligomeric silsesquioxane (POSS) endgroups at the air/water interface

POLY 618

Woojin Lee, wolee@vt.edu1, Suolong Ni, sni@vt.edu1, Byoung Suhk Kim2, Sushil K. Satija, satija@nist.gov3, Patrick T. Mather, patrick.mather@case.edu4, and Alan R. Esker, aesker@vt.edu1. (1) Department of Chemistry (0212), Virginia Tech, Blacksburg, VA 24061, (2) Polymer Program and Department of Chemical Engineering, University of Connecticut, Storrs, CT 06269, (3) Center for Neutron Research, NIST, 100 Bureau Dr. STOP 8562, Gaithersburg, MD 20854, (4) Department of Macromolecular Science and Engineering, Case Western Reserve University, 2100 Adelbert Road, Cleveland, OH 44106
The combination of non-surface active oligomeric poly(ethylene oxide) (PEO, 1 kg/mol) and closed-cage polyhedral oligomeric silsesquioxane (POSS) as endgroups on the PEO chain creates amphiphilic telechelic POSS-PEO-POSS polymers which are insoluble surfactants at the air/water (A/W) interface. Thermodynamic analyses of surface pressure-area per monomer isotherms indicate that the POSS endgroups reside at the A/W interface and that the PEO chains are squeezed out of the interface with increasing surface pressure. This conclusion is supported by X-ray reflectivity studies on Y-type Langmuir-Blodgett multilayer films which reveal a double layer structure with a double spacing of about 3.5 nm. These strategy provides a mechanism for producing new surface active species from non-surface active precursors.