On the swelling properties of pom-pom polymers: impact of backbone length

Abstract

The present work continues our previous studies of pom-pom molecule [K. Haydukivska, O. Kalyuzhnyi, V. Blavatska, and J. Ilnytskyi, J. Mol. Liq. 328, 115456 (2021); Condens. Matter Phys. 25, 23302 (2022)]. The molecule consists of a linear backbone with two branching points at both ends, with functionalities f1 and f2. Here, the main attention is concentrated on studying the impact of the central backbone length on the configurational charactersitics of complex molecule, such as size and shape ratios. We apply both a direct polymer renormalization scheme based on continuous chain model and the alternative Wei's method to analyze a set of size and shape properties of pom-pom polymers in dilute solution. The size ratio of a pom-pom and a chain polymer of the same total molecular mass is calculated with an excluded volume interaction taken into account, and estimates for asphericity are found in Gaussian approximation, whereas for the size ratio we found a monotonous dependence of the length of backbone at different functionalities of side arms. Results for asphericity show a non-trivial behaviour.

Universal properties of branched copolymers in dilute solutions

“…A generalization of the star polymer, the so-called hybrid rosette structure is obtained when 𝑓 𝑟 linear branches form closed loops, whereas 𝑓 𝑐 branches remain linear [14][15][16] (see figure 1 left-hand). The polymer macromolecule with two branching points of functionalities 𝑓 1 anf 𝑓 2 , which can be considered as two-star polymers with one common branch (the backbone) is known as pom-pom polymer [17][18][19][20][21] (see figure 1 right-hand). As more advanced polymer structures containing multiple banching points, we should also mention the dendritic macromolecules resembling the structure of a tree with multiple repeating units, which have a wide range of potential applications [12,22,23].…”