The dendrimers are a unique class of branched macromolecules with defined architectures synthesized by iterative reaction steps. Because of their highly branched structures, the dendrimers have a wide potential application in many fields, including sensing, drug delivery, catalysis, etc. In order to understand the thermal equilibrium behavior of the dendritic homopolymers in solution, we derived the self-consistent field theory (SCFT) for the dilute dendrimer solutions. The center segment is anchored on the origin of the space, and the shape of the dendrimer is assumed to be spherically symmetric. The pre-averaged interaction parameter u is employed to represent the volume exclusion interaction between the segments. We only focus on the dendrimer immersed in the θ solvent, where the volume exclusion interaction between the segments is negligible (u=0). The number density of the segments, φ(r), is calculated via systematically changing the topological parameters of the molecule, including the functionality f0 of the central segment, the functionality f of the branching points, the degree of polymerization of the spacers P, and the total generation number G. With all parameter combinations, φ(r) was found always maximized at the center and monotonically decreasing along the radial direction. Thus, the dendrimers in θ solvent obeys the "dense-core" model instead of the "dense-shell" model. Increasing f0, f and G results in the increase of φ(r) with any radius r. However, increasing P causes the decrease of φ(r) near the center region and the increase of φ(r) with larger r. The size of the dendrimer, analyzed by calculating the radius of gyration R, increases with f0, f, G and P. R calculated by our SCFT agrees well with the results obtained by the Rouse dynamics. With large f0, f and G, both SCFT and the Rouse dynamics predict the scaling law <R2>≈GPa2.
付超, 杨颖梓, 邱枫. θ溶剂中树枝形均聚物的自洽场理论计算[J]. 化学学报, 2019, 77(1): 95-102.
Fu Chao, Yang Yingzi, Qiu Feng. Self-Consistent Field Theory of Dendritic Homopolymers in θ Solvent. Acta Chim. Sinica, 2019, 77(1): 95-102.