Studies On Amphiphilic Brush-Dendritic-Like Copolymers And Thermoresponsive Dendronized Polymers Containing PAMAM Dendron

Dendritic polymers possess highly branched polymer structures. The highly branched structures endow these polymers unique properties and potential applications in sensors, catalysis and biomimetic applications. In this paper, a fashionable design to integrate the polymer brush with polyamidoamine (PAMAM) dendron is provided, and the thermoresponsive dendronized polymers based on PAMAM are also successfully prepared. The contents are as follows:1. The well-defined amphiphilic brush-dendritic copolymers (PPEOMA-b-Dm-b-(PCL)2m (m=1,2,3)) were synthesized, which bearing hydrophilic poly[poly(ethylene oxide) methyl ether methacrylate (PPEOMA) brush and a hydrophobic dendritic copolymer. The copolymers were characterized in detail by NMR, GPC and FTIR. In a selective solvent, the stable micelles can be obtained with the dropwise addition of water to the copolymers acetone solution. The critical micelle concentration (CMC) of the brush-dendritic copolymers was measured by fluorescence technique using pryene (6×10-1M) as a fluorescent probe. Furthermore, the self-assembly behavior and morphologies of amphiphilic copolymers in aqueous solution were studied by dynamic light scattering (DLS) and transmission electron microscopy (TEM). TEM images verified that different morphologies such as micelles, large compound micelles (LCM) and even Janus particles, could be formed under different content of water. On the other hand, the bulk properties of brush-dendritic copolymers were also studied by using differential scanning calorimetry (DSC), polarized optical microscopy (POM).2. A series of thermoresponsive dendronized polymers, such as poly(AzPMA-D0.5), poly(AzMA-D0.5), poly(AzMA-D0.5-COOH), were synthesized via atom transfer radical polymerization (ATRP). The structures of these dendronized polymers were characterized in detail by the combination techniques consisting of IR, NMR and GPC. Moreover, the low ctitical solution temperatures (LCST) of the dendronized polymers were studied by UV-vis. The thermoresponsive dendronized polymers with the tunable LCST properties can be potentially applied as biomaterials.