Parallel track: low creep nanomechanical parts for DMS.

Intro

While biodegradable nanomachines remain our first priority, we recognise that the pinnacle of molecular nanotechnology is diamond nanoparts operating in unison.

For that reason, we're interested in facilitating research into a promising flavour of the "direct to diamond mechanosynthesis" pathway. One that entails creating diamondoid parts out of pseudo-diamonds and using those as tools for mechanosynthesis attempts.

The joke has always been that you need diamond parts to make diamond parts. So why not lean into it? Manufactured sp3 tools and parts may be what will finally make pick-and-place tractable.

The science of building diamondoid nanomechanical parts via tip functionalisation for self assembly.

1. Picture the adamantane molecule:

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2. A raw bridgehead carbon (CH) in adamantane looks like this: cage–C–H

3. Theoretically, We could get two adamantane cages (or any other higher diamondoids) and replace their bridgehead Hs with a –CH₂–X pendant group:

cage–C–CH₂–X

So now the bridgehead carbons have an exocyclic arm sticking out toward the adjacent cage, with X sitting at the tip of those arms.

X is a thermally labile leaving group. It departs cleanly when you apply heat, without needing a catalyst diffusing through the solid.

4. What happens on heating

Step 1: X departs. Heat provides the activation energy. X leaves, taking its electrons with it or leaving them, depending on the mechanism. What remains is:

cage–C–CH₂• (radical) or cage–C–CH₂⁺ (carbocation, less likely in this context)

You now have a reactive exocyclic carbon at the tip of an arm.

Step 2: That reactive carbon of one adamantane cage is geometrically aimed at the corresponding reactive carbon on another. This can be facilitated by using the rest of the adamantane’s CH${}_2$ network to bias this geometry.

Step 3: The two reactive carbons across the interface couple, forming a C–C bond. The –CH₂– arm becomes a methylene bridge between the two cages:

cage–C–CH₂–C–cage

This is now a covalent C–C–C linkage between adjacent adamantane cages, with sp³ geometry preserved throughout.

This is not diamond!!! It is a “diamondoid nanocrystaline material” since it is filled with methylene bridges.

Regarding the methylene bridge(CH${}_2$), don’t worry about it. It's still fully sp³. The mechanical integrity argument doesn't collapse as we have a continuous covalent sp³ network. Stiffness will be lower than pure diamond but potentially comparable to diamond-like carbon or nanocrystalline diamond, which are already extraordinary materials.

What to do with these polymerized diamondoid parts:

• diamondoid UHV chamber walls, pumps & seals (after removing/replacing hydrogens with something with higher bond energy ofcourse to prevent outgassing in UHV lol)
• diamondoid NM parts (motors, gears, bearings, etc..)
• diamondoid interconnects for signal transfer.
• etc etc

The roadmap is as follows:

1. Rigorously theoretically describe the leaving group and polymerisation chemistry
2. Computationally validate.
3. Experimental synthesis of diamondoids with specific tool geometries.
4. One of these two:
   • building productive nanosystems out of these.
   • using the diamondoid tools to go on to perform the HAbstr→ C${}_2$ placement→ H passivation action sequences and produce mechanosythetic diamond.