I recently ran across a couple of neat tricks in polymer chemistry that I've not seen before. The first is this reaction: the full article yet ($) so I'm not quite sure how versatile it is - can something beside a lactone be copolymerized, such as a lactam? No matter the exact robustness of the reaction, this does open up (sorry about that pun) the possibilities for a number of new polymers that could be pretty simple to make.
The other reaction involves the crosslinking a chain with copolymerized catechol moieties. Copolymerizing a substituted catechol (aka dihydroxybenzene)[*] is a little bit tricky as the hydroxy groups need to be protected during the polymerization, but the authors report ($) a fairly straightforward process for accomplishing this. The magic though, is in the crosslinking. Two options are available. An irreversible one directly between two catechol groups, and a reversible one between a multivalent metal, in this case Fe3+.
[*] If you do decide to try this reaction, remember that catechol is a nice little skin irritant. The active ingredient in poison ivy/oak/sumac is urushiol, a catechol derivative.