Self-Assembly Behavior of Amphiphilic Poly(amidoamine) Dendrimers with a Shell of Aniline Pentamer

Abstract

A series of amphiphilic poly(amidoamine) dendrimers (PAMAM, G2-G5) composed of a hydrophilic core and a hydrophobic shell of aniline pentamer (AP) were synthesized and characterized. The modified dendrimers self-assembled to vesicular aggregates in water with the critical aggregation concentration (CAC) decreased in the order of G2 > G3 > G4 > G5. It was found that the modified dendrimers self-organized into spherical aggregates with a bilayer vesicular structures and that the dendrimers in higher generation have more order structure, which may be attributed to the crystallization induced by the compacted effect of AP segments. In addition, larger spherical vesicles were observed under acidic and alkaline conditions, as compared with sizes of aggregates in neutral medium. At low pH, the tertiary amine groups of PAMAM-AP were transformed to ammonium salts; the polarons were formed from AP units by doping with strong acids, thereby leading to the stability of vesicular aggregates being better than that in double distilled water. Nevertheless, in high pH environment, the deprotonation of PAMAM-AP caused the enhancement of π-π interactions, resulting in generation of twins or multilayered vesicles.

Salt-Responsive Fe3O4 Nanocomposites and Phase Behavior in Water

“…However, a lower intensity and broad diffraction peak centered at 2θ = 20°–24° was observed for the NCs, supporting the existence of amorphous PANI due to (100) and (110) diffraction of the polymer domains. These signatures relate to the periodicity of PANI chains perpendicular and parallel to the PANI chains, respectively. ,− The partial absence of PANI and monodisperse periodicity of the IOPNc7 composite imply that molecular packing of PANI within the NCs becomes less ordered with decreasing weight fraction of CHT (%) …”

“…Notably, the particle number increased when polymerization occurred at higher stabilizer levels. The stabilizer efficiency (manifests itself by formation of small-sized and large number of polymer particles) increases with greater stabilizer concentration . Stabilizer efficiency of CHT relates to the hydroxyl, carbonyl, and amine functional groups of the polymer backbone which can form hydrogen bonds with PANI spheres.…”

“…The stabilizer efficiency (manifests itself by formation of small-sized and large number of polymer particles) increases with greater stabilizer concentration. 42 Stabilizer efficiency of CHT relates to the hydroxyl, carbonyl, and amine functional groups of the polymer backbone which can form hydrogen bonds with PANI spheres. A reduced efficiency at 3.0% CHT was related to the attenuated accessibility of functional groups and its limited adsorption ability with the formation of fewer and larger sized particles.…”

Emergence of cationic polyamine dendrimersomes: design, stimuli sensitivity and potential biomedical applications

“…aromatic, long hydrophobic, fluorinated chains) to the hydrophilic dendrimers. 5,[9][10][11][12][13] The polyamine dendrimer-based vesicles, or dendrimersomes, resulting from their self-assembly, have emerged as promising delivery systems for various biomedical applications.…”

“…Much work has been devoted so far to the studies of polyamidoamine (PAMAM)-based amphiphilic dendrimers bearing long, soft chains at their periphery. 5,[9][10][11][12][13]35 By contrast, it is only recently that the aggregation behavior of another polyamine hydrophilic dendrimer, poly(propylene imine) (PPI), was investigated. [36][37] Page 4 of 43 Nanoscale Advances…”