Load-release of small and macromolecules from elastomers with reversible gyroid mesoporosity

A collapsed elastomeric matrix of lightly cross-linked 1,2-polybutadiene (1,2-PB) was prepared from a self-assembled 1,2-polybutadiene-b- polydimethylsiloxane (1,2-PB-b-PDMS) of gyroid morphology after the removal of the PDMS block. No mesoporosity could be observed in the material in the dry state.

However, in the gel state in the presence of a good solvent the swollen matrix did show a nanoporous structure originated from the gyroid block copolymer precursor. Nanopores can be opened or closed depending on the presence or absence of a solvent. Macromolecules like PEG of different molecular weights or small molecules like the surfactant SDS were loaded into the opened nanoporous matrix in the presence of a solvent and remained trapped.

The loaded molecules could be released again in the presence of a solvent. The load and release of the molecules in deuterated form were monitored by in situ time-resolved small angle neutron scattering, SANS. The bicontinuous gyroid pore structure is accessible to macromolecules without the need for sample pre-alignment.

The materials presented here are model systems for a novel type of load-delivery systems that could show great potential in e.g. diagnostics or drug delivery applications. © The Royal Society of Chemistry 2012.