Thermal isolation

In technology level III thermal isolation with pure hydrocarbon systems is problematic. Diamond is the worst possible thermal isolator. More generally the allotropes of carbon (diamond, lonsdaleite, graphene, nanotubes, fullerenes?) are all pretty bad thermal isolators. Structuring carbon in novel ways may yield acceptable results. (Todo: check whether macroscopic structures can be electro-statically levitated in multiple shells whit nano-scale distances in between) Regular gaps between electrically conductive surfaces can have influence on the allowed modes of electromagnetic (heat) radiation transport.

If the incremental path was taken silicates may me mechanosynthesizable to an AP aerogel like substance.
A lack of material stiffness may pose problems.

The stiff structures desirable for AP systems somewhat contradict low thermal conductance since they usually lead to a high phononic (lattice vibration) contribution to thermal conductance. Electronic contributions can be kept low more easily.