Dendritic effects: dependency of dendritic nano-periodic property patterns on critical nanoscale design parameters (CNDPs)

Abstract

The term dendritic effects has been used extensively by many dendritic polymer scientists since the early 1990s to describe certain intrinsic physico-chemical and application property patterns exhibited by dendrons and dendrimers. Until the present, this terminology has been used to report the dependency of these unique property patterns on dendritic generation levels, thus implying such effects are manifested solely as a function of their architecture and size. This review presents a deeper examination of these issues and shows that essentially all dendritic effects are clearly related to one or more and perhaps the concurrent interaction of several structure controlled parameters referred to as critical nanoscale design parameters (CNDPs). These structure controlled parameters include: (a) size, (b) shape, (c) surface chemistry, (d) flexibility/rigidity, (e) architecture and (f) elemental composition. Furthermore, it has been shown that many dendritic effects are actually architecturally driven as a consequence of congestion involving many of the CNDPs (a–d) and may be categorized into so called: (i) endo- and (ii) exo-type effects. It is noteworthy that Percec/Rosen et al. [J. Am. Chem. Soc., 2009, 131, 17500] have used these same CNDPs to predict many important dendritic effects (i.e., nano-periodic property patterns) leading to the first examples of Mendeleev-type soft matter nano-periodic tables. These soft matter nano-periodic tables provided unprecedented a priori predictions (i.e., 87–93% accuracy) of self-assembly pathways to tertiary and quaternary structures resulting from many libraries of amphiphilic dendrons based solely on the quantized CNDPs present in the dendron primary structures. In conclusion, it appears that dendritic effects as we now know them can be viewed as collections of “mini nano-periodic property patterns” that may ultimately be used to frame and define a broader encompassing Mendeelev-like system for the a priori prediction of dendritic polymer properties.