Janus-type linear-dendritic block copolymers (LDBCs) are polymers composed of segments with fundamentally different molecular architectures and chemical properties (e.g., hydrophilic and hydrophobic). Often referred to as hybrid materials, they combine the advantageous properties of both linear and dendritic (i.e., branched) macromolecules and are capable of forming various types of supramolecular aggregates in water, depending on the weight ratio between the hydrophilic and hydrophobic moieties. Juxtaposing the basic architecture of our LDBCs to that of traditional block copolymers, LDBCs afford nanomaterials with superior mechanical properties. Despite substantial precedents in the literature employing LDBCs, the majority of reported studies have focused solely on the dendritic segment attached to a single linear chain. Aiming to afford the next generation of drug delivery systems (DDS), self-assembling LDBCs comprised of a hydrophilic dendrimer of a constant MW covalently linked to a hydrophobic polyester and fatty acids were synthesize. Herein, we focus our attention on the linear segment of the copolymer as a means to improve the mechanical stability of the resulting nanoparticle via random-coil chain entanglements. With variations at the hydrophobic polyester segment, such as increasing branching density and thermal properties (low/high Tg, amorphous, crystalline), high levels of control exhibited by well-defined, regularly branched systems are achieved. The synthetic protocol to obtain well-defined LDBCs of varying architectures with high yield was confirmed via spectroscopic and chromatographic analysis. Microscopy (TEM) and light scattering (DLS) analysis indicate the size (i.e., diameters) of the nanoparticles ranging from 20-200 nm. Small angle X-ray scattering (SAXS) was employed to obtain direct structural information on the various morphological assemblies in a saturated aqueous solution. Results obtained from this study contribute to “bottom-up” approaches towards efficient biomaterials with superior properties.<br/> <br/>

Elucidating the effects of hydrophobicity and branching in amphiphilic linear-dendritic block copolymers (LDBCs)

2019 Fall National Meeting

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