Toy models of multibranched polymers: opened vs. circular structures

We study the conformational properties of complex Gaussian polymers containing \(f_c\) linear branches and \(f_r\) closed loops, periodically tethered at \(n\) branching points to either a linear polymer backbone (generalized bottlebrush structures) or closed polymer ring (decorated ring structure). Applying the path integration method, based on Edwards continuous chain model, we obtain in particular the exact values for the size ratios comparing the gyration radii of considered complex structures and linear chains of the same total molecular weight, as functions of \(n\), \(f_c\) and \(f_r\). Compactification of the overall effective size of branched macromolecules with the increasing number of loops is quantitatively confirmed. Our results are supported by numerical estimates obtained by application of Wei's method.