Right off the bat, this is a great piece. I love the intricacies of the bubbles and even though macro shots are very common these days.. this piece stands apart from them in a positive way.

Although I believe the rainbow organization of the piece is effective, I think that the border detracts from the abstract elegance of each piece themselves. Maybe if the outside of the white line was less thick or both outside and inside were roughly equivalent it wouldn't stand out so much.

The third and seventh pieces of the sequence seem a little out of place, but the seventh bother's me more than the third. When you use a composition that is so rigidly sequential, our minds naturally play the "which one is not like the other" game.

My suggestion would be to cut the third and seventh and compose the piece in couplets of three. This would give the viewer the ability to look at the piece as a whole rather than sequentially (eg. 1 - 11). This would not impede your intent with the rainbow organization if they were arranged from left-to-right due to most left-to-right reading people (assuming this was the audience you were aiming at) visually "read" artwork sequentially as such.

Cheers.