Replication of gyroid network arrays

An indication of the extremely high fidelity of electrochemical g5rroid replication is given by comparison to computer-simulated sections of the BCP template before deposition, and of the replicated material after final removal of the template (Fig. 2.19). A g5rroid simulation with a unit cell dimension of 47 nm was used to match these SEM images. 

The source of compression in the replicated network is a volume contraction of the electrochemically deposited material on heating. This is confirmed by thickness measurements of flat films (Fig. 2.22) before and after high temperature processing. Since the film cannot shrink in the lateral direction (without fracturing from the substrate), all compression is taken up by vertical compression. 

Complete filling of the template was acheived in a standard manner by monitoring the electrochemical cell current under potentiostatic operation as shown in Figs. 2.22 and 2.23. 

Example of template filling by monitoring electrochemical current, (a] Anodic current density in a 780 nm template. The current increases by a factor of 1.8 on filling of the polymer template (accounting for the steady fall in current with a single exponential decay fit), (b) Cross section of templated array after removal of PFS matrix by UV-ozone etching shows the uniform layer of overgrowth over the template surfece. 

By extension, the template matrix phase is also fully continuous, so that any material later infiltrated into the array will have complete access to every part of the network. 

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