It be more of a temporary barrier. As the ant colony grows, they'll keep trying to cross it and eventually they'll knock off the barrier with their feet. I don't think its bad for the ants though. It shouldn't have a bunch of chemicals in it though, just talc like CallMeCraven said.
Personally, I recommend olive oil (not any other cooking oil). If you can't afford/buy Fluon, olive oil has been by far the 2nd best barrier I personally use. What you do is apply it on a dish towel/rag, wipe it on the sides. And then with the dry side of the towel, lightly wipe off the excess to live a thin layer of olive oil on. I've only had one ant species cross it, and that is Monomorium ergatogyna (but they cross fluon too). Most ants, get to the olive oil and don't go past it. If you do use it, if they do cross it, either the ant is really tiny (like Monomorium) or its too thick and you'll need to re-do it.
Even using fluon, I apply both (with olive oil underneath) and never had ants escape (except one species as I said). I actually in one ant farm didn't even use fluon (didn't have it at the time), and the olive oil lasted 6 months until I re-applied it since I then got fluon too. It lasts a really long time, as long as it doesn't get wet.
Powdery barriers work okay, its just more high maintenance, and doesn't really work that great with a bigger colony. If your colony is small, its fine. Just, when they get big, you'll need something else. Or re-apply it a lot.