Synthesis and applications of gyroid-structured functional materials

The self-assembed double gyroid phase is replicated into metals and metal-oxides for the manufacture of functional materials

Our work is focused on nanostructuring of functional materials such as titania or vanadia, using porous diblock copolymer thin films with gyroid morphology. The double gyroid is a particularly interesting phase morphology of microphase separated diblock copolymers, where each of the immiscible blocks forms a triply periodic, self-supporting and continuous network or matrix. Together with its high surface area, the gyroid seems to be the perfect three dimensional structure for novel nanodevices. Using gyroid-structured materials we improve the performance of dye-sensitized solar cells, electrochromic displays, supercapacitors, etc.

Gyroid replication

Schematic of gyroid self-assembly and vanadia replication. a, Surface modication with octyltrichlorosilane and SU-8 photoresist patterning. b, P(F)S-b-PLA lm deposition and microphase separation of the block-copolymer into the double-gyroid morphology during annealing at 175 C. The red styrenic majority matrix encloses the blue interconnected lactide network. The front face shows the characteristic double wave pattern of the (211) plane. c, Selective removal of lactide yields a mesoporous template. d, Electrodeposition of vanadium pentoxide in the voided network. The deposition process is restricted to areas that are not covered by SU-8, thereby creating a design pattern in the electroplated V2O5. e, Dissolution of the polymer matrix reveals the freestanding V2O5 network. f,Assembly of a functional electrochromic nanodevice by capping with a transparent counter electrode and the injection of electrolyte. The application of 1V induces a color change.

Adolphe Merkle Institute - Chemin des Verdiers 4 - CH-1700 Fribourg - Phone +41 26 300 9254