Cryogenic transmission electron microscopy (Cryo-TEM) is one  such tool. You may see some incredible images of  the confinement of counterions inside brush layer using Cryo-TEM.  pl see the reference Wittemann et al., J. Am. Chem. Soc. 2005, 127, 9688.

This technique is operating in high vacuum, while polymer brushes have to be studied in solution if you are interested by conformational changes (which occur in solution). Hence, I do not think the technique will be very useful for problems relevant to polymer brushes.

As Dr Jonas says, the solvent causes the brushes to take a certain conformation/config. However, the Cryo-TEM freezes the brush conformation/config. and may allow studies of the frozen brush-conformation in vacuum. The handling of samples during and after freezing is critical though.

From the description of the SWAPPS technique, it sounds like it is essentially XPS done at more ambient pressure such that you could look at the interplay between solvent and polymer.  Just thought it might be a nice way to probe the swollen brush conformation.  I 'll read the Whittemann to see how cryo-TEM could be used as well. 

It would really depend on whether you can build up a depth-profile in a non-destructive way. If you could do that over a range of say hundreds of nm to microns then it could be useful, though you'd have a lot of data to model...

Cryo TEM is definitely a good option. We  this some years with a collaborator in CNRS france. We could get some incredible images of polymer brushes frozen on oil (emulsion) droplets.  But  I must caution you that it is a  time consuming experiment  and prone to artifacts.