Thermal insulation

Graphite is famously anisotropic.  Single crystals are excellent thermal conductors in two dimensions (a-axes) and poor conductors in the third (c-axis).  While it may be impossible to improve on graphite as a thermal conductor[21], the following image suggests one way to improve graphite as an insulator.

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graphite bends at rift boundary, high resolution
The discontinuities in this origami sample should accentuate the already high anisotropy of conventional graphite.  While c-axis conduction within dense graphite sheets is about three powers of ten poorer than a-axis conduction[21], heat must flow between sheets through narrow, sparse contacts.
Discontinuously stacked origami graphite will impede all three modes of thermal transport:

 C-axis conduction in discontinuous origami graphite will be especially poor if the discontinuities are numerous.  Numerous, thin graphite sheafs are desired.  The following micrograph shows that origami of nanoscale thickness can be made.

torn graphite drum

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Isolated graphite sheets of only several nanometers thickness are easily produced by splat-cooling.  We might produce thick, low density stacks of these membranes for thermal insulation by precipitating graphite onto an evolving curved melt surface.


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