Adding to my first comment, another basic problem that at least applies to organic chemical assemblies, is that easily constructed useful engineering shapes such as straight lines (acetylenes, polyenes), planes (graphene ) or spherical/ellipsoidal curves (buckminsterfullerene like structures) are always replete with free electrons. This makes them somewhat reactive in oxidative atmospheres. Everybody looked at the spherical buckminsterfullerene molecule and said “wow, a super-lubricant!” Nope, it is too darn reactive to have a useful lifetime. This is actually rather reassuring in the context of grey goo scenarios.
Excessive reactivity in oxidative atmospheres may perhaps be overcome if we use metal-organic frameworks to create useful engineering shapes (I am no expert on these so don’t know for sure). But much basic research is still required.
Adding to my first comment, another basic problem that at least applies to organic chemical assemblies, is that easily constructed useful engineering shapes such as straight lines (acetylenes, polyenes), planes (graphene ) or spherical/ellipsoidal curves (buckminsterfullerene like structures) are always replete with free electrons. This makes them somewhat reactive in oxidative atmospheres. Everybody looked at the spherical buckminsterfullerene molecule and said “wow, a super-lubricant!” Nope, it is too darn reactive to have a useful lifetime. This is actually rather reassuring in the context of grey goo scenarios.
Excessive reactivity in oxidative atmospheres may perhaps be overcome if we use metal-organic frameworks to create useful engineering shapes (I am no expert on these so don’t know for sure). But much basic research is still required.