Ah, the poster session. I like these things; they have allowed me to perfect that useful social skill of marching up to strangers, thrusting a hand out in the hope it will be shaken, and saying "Hi, I'm Katharine. Who are you?" Once in a while the tactic pays off and you learn something incredibly interesting.

Tonight's session was slightly marred, not for the first time, by the realisation that members of the press had not been issued with drinks tickets. I had experienced this at the previous ACS meeting so should have anticipated it. Instead i had to charm one of the posterees into donating one of his tickets. In return i got to learn about rotaxanes that can be stacked up to make switchable liquid crystals, in a very elegant piece of chemistry. This is the first controlled, switchable liquid crystal to be made, and no surprise that the work, done by Ivan Aprahamian (thanks for the beer Ivan) comes out of the lab of Fraser Stoddart. The work was recently published.

The poster also had a molecular carousel - an incredibly complicated molecular machine with three "axes" joined at top and bottom each holding a ring that can move up and down, independently of the other rings. Hard to describe, but a carousel, where the rings represent the galloping horses, is a good analogy.

My favourite title of the evening has to be "highly absorbing superabsorbent polymers" by Thilini Mudiyanselage, from Bowling Green State University. These are hydrogels that can absorb thousands of times their own dry weight in liquid. The lightly cross-linked 3-D polymer nets expand a lot after soaking up all that water.

As usual, a huge mix of chemistry was showcased at the poster session - from a system that gets rid of bird poo, to a poster called "Girls in science" - bet you can't guess what that was about - and try saying it without using a Muppet-esque "Pigs in Space" voice...