I am thinking about the way to attach the printed photographs to the wall but not using the frame.
And the most interesting idea for me is the use of electrostatics.
In addition I have found the following video that shows this process in action:
http://youtu.be/r0u85k5EpcE
Also I think that something like this is used in some kinds of wall-climbing robots.
So does somebody know how it works? I suppose that the materials of the objects are very important here. Probably it works because the wall and photo are made of paper, and plastic between them gets charged and consequently attracts paper. What other materials or combinations of materials can provide this effect?
And how is the electrostatic charge transferred to the material (plastic foil and paper)? I know only about objects gaining electrostatic charge after rubbing them. But in the stick from this video it must be done by some simple electric circuit…
Best Answer
I've never done the experiment with the plastic film, but as child I remember that if I rubbed a balloon on my pullover it would stick to the wall. The reason is the one you suggest. When you run the balloon on your pullover you charge it. When you bring the balloon close to the wall the charge on the ballon polarises the surface of the wall, i.e. it repels like charges and attracts unlike charges, so the surface of the wall acquires a charge opposite to the balloon. The opposite charges on the ballon and the surface of the wall attract, so the balloon sticks to the wall.
The problem with using this to fix pictures to the wall is that the charge gradually leaks away so the balloon/picture will fall off. My recollection is that the balloon would stay stuck to the wall for about an hour.
As you say, objects may be charged by rubbing them and this is called triboelectricity. Alternatively you can charge objects by touching them with something else that is charged. Because like charges repel, if you touch a charged object to an uncharged object there will be a tendancy for the charge to spread over both objects. To what extent this happens depends on the conductivity of the objects. I imagine the plastic film is a poor conductor and this is why you have to rub the Fun-Fly-Stick all over it.
I had never heard of the Fun-Fly-Stick but a quick Google suggests it's a type of Van de Graaff generator.