Experimental and theoretical investigation on surfactant segregation in imprint lithography

The effects of template surface composition on fluorinated surfactant segregation were investigated for imprint lithography with photopolymerizable vinyl ether formulations. Heptadecafluoro-1,1,2,2-tetrahydrodecyl vinyloxy-methyloxy dimethylsilane, containing a vinyl ether group, was employed as the surfactant, and blanket templates were pressed onto the liquid and illuminated with UV radiation from below. The extent of surfactant segregation to the vinyl ether-template interface before polymerization was characterized using contact angle measurements and angle-resolved X-ray photoelectron spectroscopy after removing the template from the cured vinyl ether polymer. Blanket surfaces consisting of bare quartz, high-density polyethylene, and quartz treated with tridecafluoro-1,1,2,2,-tetrahydrooctyltrichlorosilane afforded templates with different surface energy and polarity. The highest degree of surfactant segregation was found with tridecafluoro-1,1,2,2,-tetrahydrooctyltrichlorosilane-treated quartz, whereas little surfactant segregation was found for bare quartz. A thermodynamic model is developed to predict the surface segregation profiles.