Plastic Man DC Comics (Cole, J., USA, 1941-56) Our culture has made us ready…
Star Trek Sci-Fi TV series (Roddenberry, G., USA, 1966 -) Our culture has made us ready…
Linda & Valerian Sci-Fi Comic books (Christin & Meziéres, France, 1967 - ) I am ready. But how will you do it? Take it easy, dear customer! You are only risking to be surprised . . . Our culture has made us ready…
Barbapapa Children TV-series and books (Tison & Taylor, France, 1971-80) Our culture has made us ready…
Terminator II Sci-Fi Motion picture (Cameron, J., USA, 1992) Abyss Sci-Fi Motion picture (Cameron, J., USA, 1989) Our culture has made us ready…
… and technology is close
NASAs Jet Propulsion Lab
Electro Active Polymers (EAP)
Nano technology – carbon nano tubes
Miming the nature
Octopus and Sepia
Heat and light sensitive ink
Carbon ultra capacitors
Phase change materials
Shape memory polymers and alloys
Shape memory alloys
Shape memory alloys
Active acoustic coating
Dynamic materials by Tatiana Makarova
ACTUATORS Actuators provide the driving force and motion for a variety of natural and man-made requirements
Naturally occurring actuators include the muscles of animals, plant fibroplasts, cilia and flagella.
Signal from neuron.
All-Or-Nothing principle is valid for one fibre.
If impuls is strong enough, more fibres will be excited.
Cilia and flagella
Cilia and flagella are whip-like appendages of many living cells.
Functions: moving cell, moving fluids, moving small particles across the cell surface .
Cilia and flagella move because of the interactions of a set of microtubules inside
Hydraulic and pneumatic : displacement via the flow of liquid
Electromagnetic : moving motors due to an electrically induced magnetic field
Electrochemical : convert electrical energy into mechanical energy via charge induction ,
Piezoelectric : external electric field is applied to induce strain.
Magnetostrictive : strain under the influence of an applied magnetic field .
Thermal expansion : shape change with temperature
Consist of an inner tube covered by a mesh shell
Inner tube is inflated and the material expands vertically
Piezoelectric property causing it to expand when electric voltage is applied to it and return to normal when the electric voltage is cut.
Piezoelectric Actuators are solid state (ceramic) actuators that convert electrical energy directly into motion (mechanical energy)
Very fast switchers!
Electric impulse transformed in sound.
Sound transformed in electric impulse
Ferroelectric liquid-crystalline elastomer
By application of an electric field, a tilt angle is induced in a plane perpendicular to the field. The sign of the tilt depends on the direction of the electric field E.
Carbon has a unique position among the chemical elements:
Basic element of fiving substances
one of the lightest elements that forms covalently bonded solids at room temperature.
Therefore, we should not be surprised if carbon also plays a special role in nanotechnology and if a variety of technological applications are proposed.
One of these is actuators and in particular nanoactuators.
What are Nanotubes ?
Discovered by Iijima (1991)
Rolled up sheet of graphene
Capped at the ends with half a fullerene
Buckypaper is a macroscopic ensemble of nanotubes, in which the tubes form bundles and the bundles entangle to a paper like fleece.
The new nanotube threads are about 10 times stronger than buckypaper, and can be tied into knots without breaking. But they are still much weaker than many other fibres, such as iron thread. Nanotube paper and nanotube threads
Buckypaper as actuator
Nanotube actuation is caused by the geometrical expansion of the carbon–carbon covalent bond caused by charge transfer into the nanotube
Changing the voltage applied to single-walled carbon nanotube sheets causes the nanotubes to move, just like natural muscle fibres but not so ordered.
e e e e C C C C
Experimental set-up used for the measurement of the dependence of SWNT sheet length on applied potential
The Bucky Paper is set on a double-sided sticky
The tape is immersed into an electrolyte (salt water),
the bucky paper is used as a working electrode and connected to a potentiostat,
Charge injection in nanotubes
An electrolytic double layer forms at the interface between the nanotube bundles and the electrolyte.
The tubes in the bundles expand and the double layer ensures charge neutrality
Without this double layer it would be difficult to apply much charge to the nanotubes, as there would be a large electrostatic repulsion of the charge on the nanotubes.
Cantilever-based nanotube actuator
Schematic view of a ‘bimorph’ cantilever operating in aqueous NaCl.
Two strips of SWNT (grey) are laminated together with an intermediate layer of double-sided adhesive tape (white).
The initially vertical structure bends when a potential is applied between the two strips of Buckypaper.
Actuators of individual carbon nanotubes
A trench was etched into a silicon chip and a nanotube was placed across this trench. The device was placed into an electrolyte, a potential applied to the tube, and the change of the tube length was to be monitored by the displacement of an atomic force microscope (AFM) tip.
After several futile attempts, an AFM signal of the expected amplitude was observed.
As an independent check, an experiment without electrolyte was designed.
If there is only one nanotube there is no need to compensate the charge with a double layer.
The tube can be charged by applying a voltage between the tube and the bulk of the silicon substrate.
Nanoscale electromechanical systems - nanotweezers
Electrically conducting carbon nanotubes were attached to independent electrodes (A)
Voltages applied to the electrodes closed and opened the free ends of the nanotubes
The mechanical capabilities of the nanotweezers were demonstrated by grabbing and manipulating submicron clusters (B)
and nanowires (C).
Elastic Response of Carbon Nanotube Bundles to Visible Light A filament with one end attached on the electrode and the other end free The free end displaced as much as 1.3 mm in the direction of light A thick filament with two ends fixed to electrodes. Illumination of the halogen lamp. The middle part of the filament displaced about 0.16 mm in the direction of light
Carbon is a basic element of living substances, and it is going to be a biocompatible device
Can the materials be used in a human body application where they will rub against other surfaces? Most materials are very abrasive and hard.
Carbon is a good structural member .
Possible applications: Artificial muscles
Reversing the process would allow the nanotubes to be used as energy generators. Bending the tubes back and forth would create an electric current.
This would be good for ocean waves because they give and release a mechanical load as the waves go up and down.
Now we know the nanotubes move when we apply a charge, we can start to look at how they behave as energy generators
Using single nanotubes as electrically driven robot-arms, called actuators, in tiny machines is an even longer-term goal.
"I think it will take about 20 years for these to exist," says Dr Roth. "You not only have to have an actuator, but also other elements which control this. So a lot of development has to be put in."
Other materials which can be used as actuators already exist, such as conducting polymers, but nanotube actuators could work harder, faster and longer than these.
Small but powerful: Carbon Nanotube Bimorph Actuators and Force Sensors
The nanotubes become elongated or shortened when biased at negative or positive voltage,
One could produce opposing changes in length in pairs of side-by-side, oppositely-biased nanotubes, resulting in a lateral deflection of the unsecured tube ends,
These devices would make possible novel microelectromechanical systems, possibly even microscopic robots.
Carbon Nanotubes would grow out from catalytic metal dots on electrodes, eventually becoming attached to each other by van der Waals forces to form a bimorph actuator or sensor.
The Nanotechnology Ecology: The New Green Manufacturing Since the industrial revolution, manufacturing has been creating unavoidable, wasteful by-products. These by-products are usually harmful to life yet too expensive to disarm. Carbon: No Waste...No By-Products...No Slag...Nothing to Dump or Pollute. Nanotechnology and Ecology meet in the new field of Nanoecology