Τίτλος:
Polymer grafted Janus multi-walled carbon nanotubes
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
We describe a novel and facile strategy to modify the surface of carbon nanotubes (CNTs) with two chemically different polymer brushes utilizing the 'grafting from' technique. A [4 + 2] Diels-Alder cycloaddition reaction was used to functionalize multi-walled carbon nanotubes (MWNTs) with two different precursor initiators, one for ring opening polymerization (ROP) and one for atom transfer radical polymerization (ATRP). The binary functionalized MWNTs were used for the simultaneous surface initiated polymerizations of different monomers resulting in polymer grafted MWNTs that can form Janus type structures under appropriate conditions. 1H NMR, FTIR and Raman spectra showed that the precursor initiators were successfully synthesized and covalently attached on the CNT surface. Thermogravimetric analysis (TGA) revealed that the grafted polymer content varies when different monomer ratios and polymerization times are used. The presence of an organic layer around the CNTs was observed through transmission electron microscopy (TEM). Differential scanning calorimetry (DSC) proved that the glass transition (Tg) and melting (Tm) temperatures of the grafted polymers are affected by the presence of the CNTs, while circular dichroism (CD) spectra indicated that the PLLA α-helix conformation remains intact. © 2009 The Royal Society of Chemistry.
Συγγραφείς:
Priftis, D.
Sakellariou, G.
Baskaran, D.
Mays, J.W.
Hadjichristidis, N.
Λέξεις-κλειδιά:
Circular dichroism spectra; Diels-Alder cycloadditions; Different precursors; FTIR; Functionalized; Grafted polymers; Grafting from; Helix conformation; Monomer ratio; Organic layers; PLLA; Polymer brushes; Polymer-grafted; Raman spectra; Surface initiated polymerization; TEM; Through transmission; Type structures, Atom transfer radical polymerization; Carbon nanotubes; Cycloaddition; Dichroism; Differential scanning calorimetry; Fourier transform infrared spectroscopy; Free radical reactions; Functional polymers; Glass transition; Grafting (chemical); Monomers; Multiwalled carbon nanotubes (MWCN); Polymers; Raman spectroscopy; Thermogravimetric analysis; Transmission electron microscopy, Ring opening polymerization, Alnus
