142 Advances in Polymer Science Editorial Board: A. Abe. A.-C ...

102 N. Hadjichristidis, S. Pispas, M. Pitsikalis, H. Iatrou, C. Vlahos
solvent. In a selective solvent however the cross interactions are as effective as in
the macroscopic state of common theta or a common good solvent depending on
the solvent conditions within the homopolymer part. The dependence of length
fraction of B arms on the ratios g is shown in Fig. 4. Miktoarm stars A n B m , where
A or B are deuterated are necessary in order to evaluate these theoretical predictions.
The same group also calculated the dimensionless ratios s G and g for miktoarm
star copolymers by means of off-lattice Monte Carlo simulations [64]. The
model considers Gaussian units with Lennard-Jones intramolecular interactions
whose parameters have been set to mimic the various macroscopic states. Polymers
of the A 2 B, A 2 B 2 , A 2 B 4 , A 3 B 3 and A 6 B 6 type with equal length branches and
total number of units N=24, 48, 84, 108, 144 and 204 have been generated. The
Pivot algorithm was used for the generation of the Monte Carlo sampling. The
values of the ratios extrapolated to the limit of large molecular weights are presented
in Table 1.
Table 1. The extrapolated values of the dimensionless ratios sG , and by Monte
Carlo calculations. The values in brackets are data by Renormalization Group analysis
g SA g G A
s G
g SA
s G
g SA
g GA
s G
g SA
g GA
A 2 B A 2 B 2 A 2 B 4 A 3 B 3 A 6 B 6
1.518±0.013
(1.498)
1.074±0.15
(1.127)
1.419±0.005
(1.374)
1.833±0.024
(1.648)
1.103±0.013
(1.254)
common theta
2.207±0.016
(1.997)
1.140±0.020
(1.508)
selective solvent (theta for A)
1.605±0.015
(1.486)
1.920±0.021
(1.748)
2.454±0.022
(1.971)
1.120±0.009
(1.413)
1.980±0.018
(1.729)
5.021±0.050
(2.943)
1.119±0.013
(1.872)
3.054±0.038
(2.457)
1.061±0.009 1.107±0.018 1.173±0.014 1.150±0.009 1.207±0.010
1.258±0.020 1.371±0.014 1.584±0.018 1.590±0.027 2.093±0.035
1.294±0.005
(1.249)
1.424±0.009
(1.324)
common good
1.562±0.015
(1.498)
1.616±0.017
(1.486)
2.102±0.037
(1.971)
1.037±0.004 1.068±0.004 1.129±0.008 1.102±0.004 1.151±0.003
1.086±0.007 1.171±0.009 1.321±0.015 1.285±0.011 1.529±0.007
artificially segregated
s G 3.497±0.004 6.053±0.003 9.311±0.002
g GA
2.868±0.004 3.484±0.003 5.141±0.002