2-dimensional network formation from a graft copolymer at the air-water interface

The UV induced cross-linking of a well defined graft copolymer polynorbornene-g-poly(ethylene oxide) at the air-water interface has been investigated. Network formation has been monitored qualitatively by observing changes in surface pressure with UV exposure time working under constant area conditions. Surface film concentration has been used as the design parameter to manipulate initial film organization, and consequently position of the functional groups. Exposure of the copolymer film to UV light at different surface concentrations in the liquid condensed region shows the closer the molecules pack together the faster the cross-linking reaction, while no cross-linking occurs when the molecules are far apart in the liquid expanded state.