  We report on the hot roller embossing of polymer sheets for the creation of
microfluidic structures. Measurements conducted on 100 $\mu$m features showed
that the lateral dimensions could be replicated to within 2% tolerance, while
over 85% of mould depth was embossed. Feature sizes down to 50 $\mu$m and
feature depths up to 30 $\mu$m had been achieved. At lower temperatures,
asymmetric pile up of polymer material outside embossed regions was observed
with higher pile up occurring on the trailing side of the embossed regions.
