There's a report in Macromolecules about new way to nano-size common clay particles and make them compatible with a wide range of polymers.
This looks to me like it might be worth getting excited about. The researchers used a new exfoliating agent [*], a resorcinol bis(diphenyl phosphate) with montmorillonite. Not only did they get good exfoliation, but by using a phosphate, they also achieved (at least partial) fire protection. And then perhaps best of all, they were able to make compatible blends with PMMA, PC and PS, the last one supposedly not being possible with standard exfoliation. The report (open access) is quite extensive and well documented.
[*] Clays consist of layers of various silcates. The key to creating a good nanocomposite is to break these layers up - exfoliate them - by adding various chemicals to neutralize the charges between the layers. Once broken up, proper dispersion then is possible - still no small challenge, but certainly impossible without exfoliation.