Revision as of 17:48, 7 August 2017

A crystal of calcite (a polymorph of calcium carbonate CaCO₃) one of a few attractive bio-minerals

semi biomimetic biominerals

Overview

This Level is the most unknown yet. It might be skipped (see "vacuum" section).
The nature of the tooltips for the next technology level in that operate in an environment of practically perfect vacuum is pretty clear by now but there are no tooltips for T.Level II yet - neither proposed nor analyzed.

By definition we have reached technology level I here and have full robotic control. The task is to switch from block level precision APM to positional atomic precision (P-APM) here (by increasing stiffness). Needed are minimal molecular blocks as templating core tooltips with which stiff covalent structures that can be built under solution. There are bio enzymes that do biomineralisation but it seems very unlikely that they will be used as they are. (See Evolution & de-novo protein engineering).

Note: Current (2014) research in bio-mineralisation is focused on the artificial in vitro recreation of hierarchical bio composite materials due to their seductive superior properties. Research for technology level II is interested in flawless (and brittle) single crystalline material instead (for systematic capability expansion). Good material properties are introduced via metamaterial principles instead via composite materials. It thus requires a differing focus on the core principle of biomineralisation (templation) and the artificial mechanosynthetic application of them e.g. a demo with SPM microscopy in technology level 0.

To investigate:

• How to find methods to create structures with as freely choosable geometries as possible?
• How to do mechanosynthesis for technology level III with the materials used in this level? e.g. how to mount DC10c onto a pyrite/silicate/... robotic system?
• [Todo: will vacuum housing only suffice? - gas tightness of bio minerals]

• preciseness: which biomineralisations can naturally or could artificially produce true non amorphous single crystals?
• positional precision: some biomineralisations seems to lack positional atomic precision in the spots where material is added (existence of silica deposition vesicles SDV's indicate that) in-how-far can the templating core be used to introduce it?
• in case of loose hydrated silicate crystals - are they still stiff enough?

Vacuum

Creation of sufficient vacuum is the main reason for this intermediate technology step. If with technology level I sufficiently tight vacuum micro capsuled cannot be built then This technology level must provide them for the next step to technology level III.

Due to e.g. hydrogen adsorption in crevices or too big structural holes gas tight seals may be hard to create in technology level I. Note that examples like the proton pump do not give information about back diffusion rate in foldamer or other self assembled systems.

Combining technology level I with bulk technology may be sufficient though. E.g. building structural DNA nanotechnology micro-capsules and coating them with gold to seal them tight.

Product stability

Concentration should be well below levels where crystallization starts autonomously from over-saturation. Concentration should be well above levels where the crystal dissolves. Diffusion from and to the crystals surface must be close to nil at least in a certain concentration regime. There must be a hysteresis with a not too small bistable regime. (glass does not significantly dissolve in pure water) This must be true for all crystal planes steps and nucleation sites. (nucleation site protection?) Nucleation should only be mediated by the templating core.

Surface passivation

• What about surface passivation ?
• could terminating OH groups of adjacent contacting, sliding or pressed together surfaces fuse together under H₂O generation ?
• OH groups are angled and thus have one rotational degree of freedom -> how does this influence surface-surface friction ?

Biomineralisation

Biomineralisation is the natural place to learn from. But the current research direction is focused too much on the artificial recreation of bulk hierarchically structured polypeptide mineral composite biomaterials instead of the (simpler) core synthesis process which is all that's needed for technology level II. Learning from biology is not blatantly copying it. With rising technology levels we want to get away from biology ASAP to gain the benefits of superlubrication, superior material properties and most importantly systematic extensibility.

The idea is to copy just the crystal formation templating core configuration (not the whole polypeptides whose shapes are mainly responsible for vague site specificity) and guide it robotically by means of technology level I. Usage of partial machine phase at the tips (imagine randomly chattering teeth on a robot tip) could be allowed and may be beneficial or may not.

List of some Minerals of interest:

• Silicates
• Pyrite
• Calcite & Aragonite
• Magnetide
• Hydroxyappatite
• Periclase (MgO)?
• ...

Some information about Silicate systems: [1] [2]

Equilibrium

Calcite and Aragonite have the nice property that they become more soluble with rising pressure and thus less soluble with sinking pressure. This can be seen in the deep sea where there is a certain level (the lysocline) where those minerals start to dissolve rapidly but recrystallisation is still high enough to preserve some of the minerals. Even deeper one finds the ACD an CCD lines where all of those two minerals get dissolved.

For mechanosynthesis this means after pressure was applied to add a building block it won't come off right again. Unaided crystallisation of solvated building blocks seems to be suppressed for another reason [Todo: check which]

Other biomineralisation minerals must have means for supporting a solvation-crystal bistable situation too. Can this bistability be hard enough to allow for sufficiently long time of preservation of atomic precision to build useful parts? [Todo: Check if there are any examples of biomineralisation where the surface shape is AP. (not only the crystal structure like in many nanoparticles)]