Preparation of evaporation-resistant aqueous microdroplet arrays as a model system for the study of molecular order at the liquid/air interface.

Aqueous arrays of microdroplets typically sized between 2 and 10 microm were generated by microfluid contact printing and stabilized with respect to evaporation by incorporation of poly(ethylene oxide). The arrays are used as a model system for the study of structure formation at liquid/air or liquid/liquid interfaces. In particular, we demonstrated the self-organization of fatty acids with photopolymerizable diacetylene units (10,12-pentacosadiynoic acid) at the liquid/air interface of the microdroplets. Topochemical polymerization behavior of this compound and the autofluorescence property of the resulting polyconjugated polymer are appropriate features to prove the molecular order of the amphiphilic molecules at the interface.