Friction, and really any kind of 'contact' between things is just electrons repelling. Some ideas for dark matter don't interact in any way other than gravity, so your idea is pretty mainstream on that, but there's basically no evidence that dark matter exists in some specific form, and in fact every experiment seems to constrain the possible forms it could have more and more. It's still possible it exists, but I would suspect that whatever the explanation is for the 'missing' matter will be pretty revolutionary.