[extropy-chat] Casimir Torque Project

[Adrian Tymes]

--- Eugen Leitl <eugen at leitl.org> wrote:
> On Thu, May 05, 2005 at 06:01:31PM -0700, Adrian Tymes wrote:
> > --- Eugen Leitl <eugen at leitl.org> wrote:
> > > Kidding aside, have you considered functionalizing your
> MEMS/NEMS?
> > > You'd have
> > > to do wet chemistry for that, though, too.  
> > 
> > Define "functionalizing".  I'm just aiming for a discrete unit,
> 
> Chemical functionalising, attaching functional groups to the surface
> of your
> discrete MEMS/NEMS part. By bringing such differently functionalized
> parts into
> proximity of your reaction site (e.g. by shuttling them on a plane
> surface) 
> you'd do chemistry by numeric control (mechanosynthesis).

No, I hadn't considered that.  While this particular unit would be no
good for that (if it works, it will just spin without manual control;
if it doesn't work, it will just sit there), I can see how the
techniques I'm doing would be applicable...although, at the scales I'm
building at, I'd wind up with chemistry in batches of hundreds of atoms
(and possibly not complete mixing, either) instead of doing things one
atom at a time.

Although...as part of the support for this experiment, to help make it
observable (actually seeing things, like whether a ring rotates, at
that scale is difficult to say the least - SEMs are not as easy to use
as optical microscopes), I came up with a system of gears that would in
turn rotate a part large enough to be seen optically (at 1000x or so,
near the limits of optical microscopy).  I think I see how I could use
said gears, if actively and selectively driven, to shuttle around pegs
on a board, where each peg would have a functionalized surface.  (At
one edge of the board would be mechanisms for scraping off the surface
of the pegs and re-functionalizing them.)  If you had two of these
boards, face to face, at controllable separations, you could possibly
do something like mechanosynthesis.  (You'd need the control the board
separation in all three dimensions, so that you could have a peg on one
board tap a peg on another board on top or on the sides.)

Hmm...sorry if that doesn't make much sense.  And I can see a few
problems with it already (like, depositing new chemicals that you want
to interact on only the desired regions of a peg, once you start
seriously building up...although if you could remove unreacted material
but not reacted material after the reaction, that wouldn't be as much
of a problem).

> > interacting with the outside world only by providing a (near)
> constant
> > voltage differential between two areas on its surface, built by
> > traditional top-down approaches.
> 
> While direct writing as a pure top-down technique scales from macro
> to nano,
> you can also combine top-down and bottom-up (such as functionalizing
> ~nm parts).

This is true.  Arguably, I am using at least one bottom-up step, to
deposit metal into holes that have previously been formed.  However,
the steps that control the actual shape of the device are all top-down.