# What materials can I use for the roller and band of a DIY Van de Graaff generator?

I have made a VDG generator with a rubber band as the belt and a glass roller. It doesn't seem to work. I think the rubber band may be conductive.

I was thinking of using other materials for the band and the roller, such as:

+------------+--------------------------+
| Roller     | Band                     |
+------------+--------------------------+
| Glass      | Rubber from a balloon    |
| Glass      | Strip from a plastic bag |
| Human Hair | Rubber from a balloon    |
| Glass      | Silk                     |
| Glass      | Felt                     |
+------------+--------------------------+


Which of these pairs would work, and why?

As well as mechanical properties and lack of conductivity you need a means of creating the charge to be transferred. The following table gives the relative amount and the polarity of charge generated by various combinations of material.

There are may such lists available but this looks better than many, and includes some comments on 'incorrect" information available elsewhere.

A Santoprene rubber belt with a polyurethane roller looks like an interesting combination.

Alpha Lab Inc's The TriboElectric Series

Polyurethane foam on Teflon looks worth trying!

When researching materials, the final comment on the above referenced page is a warning about inaccurate data and may be worth noting:

A triboelectric series table has been circulating on the internet, and it contains various inaccuracies. Though attribution is rarely given, it appears to be mostly from a 1987 book. It lists air as the most positive of all materials, polyurethane as highly negative, and various metals being positive or negative, apparently based on their known chemical electron affinities, rather than on electrostatic experiments.

The page provides additional details to back their warning.

• Is your answer missing the final comment that you mentioned? The end of your answer doesn't seem to read correctly to me. – user16 Mar 20 '15 at 14:17

Glass does not create much charge from friction because glass is in the form of a crystal structure where at high temperatures or high friction levels, their bonds begin to break out on obtuse-to-reflex-angular limbs, at the glass transition temperature, they become so reflex bonded that they become rubber. These atoms do not give off any charges. The charges just end up geometrically transformer on spead out angles. They do not leave the molecule.

I would use urethane skateboard wheels for the rollers and a cut-up bicycle inner tube for the band.