title: 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.
authors.affiliation: Department of Chemistry, Center for Nanotechnology at CYCU, Chung-Yuan Christian University , Chung Li 32023, Taiwan , R. O. C.
authors.forename: Wei-I
authors.initials: WI
authors.lastname: Hung
authors.forename: Chi-Hao
authors.initials: CH
authors.lastname: Chang
authors.forename: Ya-Han
authors.initials: YH
authors.lastname: Chang
authors.forename: Pei-Shan
authors.initials: PS
authors.lastname: Wu
authors.forename: Chih-Bing
authors.initials: CB
authors.lastname: Hung
authors.forename: Kung-Chin
authors.initials: KC
authors.lastname: Chang
authors.forename: Mei-Chun
authors.initials: MC
authors.lastname: Lai
authors.forename: Sheng-Chieh
authors.initials: SC
authors.lastname: Hsu
authors.forename: Yen
authors.initials: Y
authors.lastname: Wei
authors.forename: Xin-Ru
authors.initials: XR
authors.lastname: Jia
authors.forename: Jui-Ming
authors.initials: JM
authors.lastname: Yeh
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D050091:Dendrimers / Q000138:chemical synthesis* / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D015394:Molecular Structure; D010316:Particle Size; D011073:Polyamines / Q000138:chemical synthesis* / Q000737:chemistry; D013499:Surface Properties; D013501:Surface-Active Agents / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000814:Aniline Compounds; D050091:Dendrimers; C531249:Poly(amidoamine); D011073:Polyamines; D013501:Surface-Active Agents; C023650:aniline