Colloidal particles have been used extensively for stabilizing oil-water interfaces in petroleum, food, and cosmetics industries. They have also demonstrated promising potential in the encapsulation and delivery of drugs. Motivated by challenging applications that require protecting and transporting active agents across the water-oil interfaces (such as in situ cracking of hydrocarbon molecules), we report our successful design, synthesis, and validation of a unique type of bi-compartmental targeting vehicle that can encapsulate catalytic molecules, find and accumulate at oil-water interface, release the catalysts towards the oil phase, and perform hydrogenation reaction of unsaturated oil. This vehicle is based on colloidal dimers that possess both structural and interfacial anisotropies between two compartments. We encapsulate active species such as fluorescent dye and catalytic molecules in one lobe which consists of uncrosslinked polymers, while the other polymeric lobe is highly crosslinked. Although dimers are dispersible in water initially, the uncrosslinked lobe swells significantly upon contact with a trace amount of oil in aqueous phase. The dimers then become amphiphilic, migrate toward, and accumulate at the oil-water interface. As the uncrosslinked lobe swells and eventually dissolves in oil, the encapsulated catalysts are fully released. We also show that hydrogenation of unsaturated oil can be performed subsequently with high conversion efficiency. By further creating the interfacial anisotropy on the dimers, we can reduce the catalyst release time significantly. Our work demonstrates a new concept in making colloidal emulsifiers and phase-transfer vehicles that are important for encapsulation and sequential release of small molecules across phase boundaries.   <br/>

Bicompartmental phase transfer vehicles based on colloidal dimers with anisotropic structural and interfacial properties

249th National Meeting (2015)

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