title: Nanotubes protruding from poly(allylamine hydrochloride)-graft-pyrene microcapsules.
abstract: Protrusion of one-dimensional nanotubes or nanorods from the poly(allylamine hydrochloride)-graft-pyrene (PAH-Py) microcapsules was discovered when the microcapsules were incubated in pH 0 and pH 2 solutions, respectively. Micelles assembled from deliberately synthesized PAH-Py polymers were also able to transform into one-dimensional structures, demonstrating the chemistry driven nature of the phenomenon. The one-dimensional nanotubes consisted of only 1-pyrenecarboxaldehyde with ordered π-π stacking, and showed a helical structure and anisotropic property. The hydrolysis of Schiff base and its rate at different pH values (10 times slower at pH 0 than at pH 2) played a key role in determining the final nanostructures, and the linear PAH directed the regular building up process especially for the nanotubes. Hollow capsules budded with nanotubes or nanorods mimicking the cellular protrusion of filopodia were successfully prepared by tuning the incubation pH and time. These results and the proposed mechanism open new opportunities for design of novel micronanostructures and materials for nanoscience, and biological and other advanced technologies.
authors.affiliation: MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Zhipeng
authors.initials: Z
authors.lastname: Wang
authors.forename: Helmuth
authors.initials: H
authors.lastname: Möhwald
authors.forename: Changyou
authors.initials: C
authors.lastname: Gao
mesh_terms: D002214:Capsules; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D011073:Polyamines / Q000737:chemistry*; D011721:Pyrenes / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D002214:Capsules; D046911:Macromolecular Substances; D011073:Polyamines; D011721:Pyrenes; C063994:polyallylamine; C030984:pyrene