Influence of the Growing Flexible Shell on the Molecular Behavior of Hybrid Dendrimers

Abstract

A versatile approach to the synthesis of hybrid dendrimers composed of a rigid aromatic core and a flexible carbosilane shell is proposed. For this, carbosilane monodendrons of the first, second, and third generations were linked to a Muellen-type polyphenylene dendrimer via the copper-catalyzed azide−alkyne cycloaddition reaction. A series of hybrid dendrimers with a fixed phenylene core size and various carbosilane peripheries were synthesized to clarify the influence of a growing flexible shell on thermal and rheological dendrimer properties. Small-angle X-ray scattering experiments and density functional theory calculations revealed that the dendrimers form a columnar phase with hexagonal (G1, G2) and orthorhombic (G3) types of packing.

Multiarm Star-Shaped Polydimethylsiloxanes with a Dendritic Branching Center

“…The unexpected diffusion coefficient results were attributed to the increased aggregation tendency of multiarm objects. Similar to dendrimers [ 38 ], while dried, multiarm stars form metastable aggregates that are stable under normal conditions. They become completely destroyed when dissolved; therefore, we see monomodal narrowly dispersed signals on GPC or DLS.…”

Thermodynamic Properties of the First-Generation Hybrid Dendrimer with “Carbosilane Core/Phenylene Shell” Structure

“…A new direction in dendrimer chemistry can be attributed to the synthesis and study of physicochemical properties of hybrid dendrimers consisting of two chemically different dendritic segments, each of which has an independent highly branched molecular architecture. The arrangement of the dendritic blocks in a different manner (i.e., a flexible core and a rigid shell or vice versa) allows for a controllable synthesis of principally new dendrimers with the desired characteristics [ 35 ]. The results of our calorimetric investigations of the widespread families such as carbosilane [ 36 , 37 , 38 ], siloxane [ 39 , 40 , 41 ], and polyphenylene [ 42 , 43 ] dendrimers with different molecular structure of the inner sphere and the surface functional groups were published earlier.…”

Adsorption of Silicon-Containing Dendrimers: Effects of Chemical Composition, Structure, and Generation Number

“…Dendrimers of the siloxane families, synthesized about 30 years ago [ 37 , 38 ], have just begun to be studied [ 29 , 30 ], and their modeling is very interesting and has a predictive value. Furthermore, recently, some works appeared on the synthesis and study of physical properties of hybrid dendrimers consisting of segments of various chemical natures [ 39 , 40 ], which have strong potential for the creation of membrane materials. In this regard, computer simulations of the adsorption of dendrimers at the atomistic level may provide some insight into how the individual elements of different chemical nature work for the targeted synthesis of materials with desired properties.…”