DENSITY PROFILES OF SIMULATED COMBBURST MOLECULES

The growth behavior and resulting intramolecular characteristics of combburst systems are simulated by using the kinetic self-avoiding-walk algorithm. Simulated combburst molecules characterized by T (= 2-5) teeth and flexible spacers of P (= 2-6) steps are compared to starburst analogues. Intramolecular radial density distributions from the center of mass of the combburst molecule as a function of P exhibit a characteristic "core" region appearing immediately, delineating two regimes of growth. This is in contrast to their starburst analogues, where the core region is not seen until the third generation. Generally, the density distributions for all (T,P) indicate that the branches of the combbursts are highly folded, spanning the entire molecule throughout growth. The ensemble-averaged radius of gyration, R(g), of the molecule is characterized by R(g) approximately M-rho-P-nu throughout growth for all T. The apparent size exponents rho and nu change throughout growth with rho = 0.22 +/- 0.05 and nu = 0.50 at high molecular weights, providing evidence of transitional growth resulting from the modified Cayley tree branching nature of starburstlike systems.