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Nanocapsules based on carbon nanotubes-graft-polyglycerol hybrid materials

Adeli, M ; Sharif University of Technology | 2009

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  1. Type of Document: Article
  2. DOI: 10.1088/0957-4484/20/48/485603
  3. Publisher: 2009
  4. Abstract:
  5. In this work the effect of a conjugated macromolecule on the conformation of CNT was studied. Typically polyglycerol (PG) was covalently grafted onto the surface of multi-wall carbon nanotubes (MWCNTs) and MWCNT-graft-PG (MWCNT- g-PG) hybrid materials were obtained. Dynamic light scattering (DLS) experiments showed an average diameter around 100nm for MWCNT- g-PG hybrid materials in water. The difference between this size and the expected size for MWCNT- g-PG hybrid materials (the length of pristine MWCNTs was several micrometers) was assigned to the effect of the grafted PG on the conformation of MWCNT in the solution state. Transmission electron microscopy (TEM) evaluations showed a change in the shape and conformation of MWCNT- g-PG hybrid materials during the time so that they were in a core-shell shape in a fresh sample but over time they changed to dendritic-and finally nanocapsule-like structures. According to ultraviolet-visible (UV-vis) experiments it was found that MWCNT- g-PG hybrid materials were able to encapsulate small guest molecules such as ferrocene, confirming nanocapsule-like structures for hybrid materials in the solution state. Based on these observations it was suggested that non-covalent interactions between highly hydrophilic PG and highly hydrophobic MWCNT led to changes in the conformation of MWCNT from a linear to nonlinear state. In order to investigate the role of hydroxyl end functional groups of PG as being responsible for non-covalent interactions such as hydrogen bonding, they were reacted with opened MWCNTs (MWCNT-COOH) to achieve MWCNT- g-PG- g-(MWCNT)n structures. TEM images showed an extended conformation for MWCNT- g-PG- g-(MWCNT)n hybrid materials which confirmed the key role of hydroxyl end functional groups of PG on the conformation of MWCNTs. To evaluate the ability of MWCNT- g-PG- g-(MWCNT)n hybrid materials to encapsulate and support guest molecules, palladium nanoparticles were loaded and transported by these hybrid materials and their reactivity toward Heck reactions was also investigated. © 2009 IOP Publishing Ltd
  6. Keywords:
  7. Average diameter ; Core-shell shape ; End-functional groups ; Ferrocenes ; Guest molecules ; Heck reactions ; Hydrogen bondings ; Multi-Wall Carbon Nanotubes ; Non-covalent interaction ; Nonlinear state ; Palladium nanoparticles ; Polyglycerols ; TEM ; TEM images ; Carbon nanotubes ; Conformations ; Dendrimers ; Dynamic light scattering ; Fluorine containing polymers ; Functional groups ; Grafting (chemical) ; Hydrogen bonds ; Iron compounds ; Multiwalled carbon nanotubes (MWCN) ; Nanocapsules ; Palladium ; Transmission electron microscopy ; Hybrid materials ; ferrocene ; glycerol derivative ; multi walled nanotube ; nanocapsule ; polyglycerol ; unclassified drug ; article ; carbon nuclear magnetic resonance ; Heck reaction ; hydrogen bond ; light scattering ; macromolecule ; nanoencapsulation ; priority journal ; transmission electron microscopy ; ultraviolet radiation
  8. Source: Nanotechnology ; Volume 20, Issue 48 , 2009 ; 09574484 (ISSN)
  9. URL: https://www.ncbi.nlm.nih.gov/pubmed/19880984