title: Spontaneous unilamellar polymer vesicles in aqueous solution.
abstract: A unilamellar polymeric vesicle is a self-assembled structure of a block copolymer that forms a spherical single bilayer structure with a hydrophobic interlayer and a hydrophilic surface. Due to their enhanced colloidal stability and mechanical property, controllable surface functionality, or tunable membrane thickness, polymeric vesicles are useful in nano and bio-science, providing potential applications as nanosized carriers for catalysts, drugs, and enzymes. For fabrication of a unilamellar vesicle, however, preparative procedures with a few steps are inherently required. Herein, without complicated preparative procedures, we report spontaneous unilamellar polymeric vesicles with nanometer sizes (<100 nm), which are prepared by simply mixing a triblock copolymer, Pluronic P85 (PEO26PPO40PEO26), and an organic derivative, 5-methyl salicylic acid (5mS), in aqueous solution. Depending on the 5mS concentration and the temperature, the P85-5mS mixtures presented various self-assembled nanostructures such as spherical and cylindrical micelles or vesicles, which were characterized by small angle neutron scattering and cryo-TEM, resulting in a phase diagram drawn as a function of temperature and the 5mS concentration. Interestingly the critical temperature for the micelle-to-vesicle phase transition was easily controlled by varying the 5mS concentration, i.e. it was decreased with increasing the 5mS concentration.
authors.affiliation: Neutron Science Division, Korea Atomic Energy Research Institute, 1045 Daedeok-daero, Yuseong-gu, Daejeon, 305-353, Republic of Korea. taehwan@kaeri.re.kr.
authors.forename: Tae-Hwan
authors.initials: TH
authors.lastname: Kim
authors.forename: Chaeyeon
authors.initials: C
authors.lastname: Song
authors.forename: Young-Soo
authors.initials: YS
authors.lastname: Han
authors.forename: Jong-Dae
authors.initials: JD
authors.lastname: Jang
authors.forename: Myung Chul
authors.initials: MC
authors.lastname: Choi
mesh_terms: D002384:Catalysis; D004337:Drug Carriers / Q000737:chemistry; D008823:Micelles; D049329:Nanostructures / Q000737:chemistry; D020442:Poloxamer / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D012459:Salicylates / Q000737:chemistry; D013696:Temperature; D053835:Unilamellar Liposomes / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D004337:Drug Carriers; D008823:Micelles; D011108:Polymers; D012459:Salicylates; D053835:Unilamellar Liposomes; D014867:Water; D020442:Poloxamer; C520964:5-methylsalicylic acid