At temperatures above the glass transition temperature (Tg) there are two major molecular motions in this copolymer: a backbone motion (the rotational motion about single bonds) and a methyl side group rotation.
The influence of the side group rotation on the surrounding is very limited.
In a parallel group experimental design, respondents from the origami group (rotation training), after 18 h of training, significantly increased their performance on a test of mental rotation.
The dependence of the potential energy profile for the −[NH2CH3]+ group rotation on the catechol ring and side-chain OH group orientation has been also examined.
In addition, a new minimum associated with the motion of the polycarbonate is observed at the temperature and time scale of the ester group rotation of the PMMA.
As the temperature is further decreased to about −175°C, well below the β-transition observed in d.m.a., the methyl side group rotation slows down, suggesting that the methyl rotation may be associated with the observed β relaxation process.
Such conclusions were supported by variable temperature infrared data, which indicated increased methyl and methylene group rotation to yield conformational disordered states (con-dis) of various energies with increased temperature.
In both cases, we found that the molecular mechanism of oxylcarbonyl side group rotation combined with reasonable constraints on movements of the neighbouring side groups gave theoretical activation energy requirements which were in good agreement with those determined from the experiment.
For both groups, rotation did affect overall performance but did not seem to alter the magnitude or duration of the AB.
