Functionalization of Single-walled Carbon Nanotubes with Thermo-reversible Block Copolymers and Characterization by Small-angle Neutron Scattering.
We demonstrate a protocol for single-walled carbon nanotube functionalization using thermo-sensitive PEO-PPO-PEO triblock copolymers in an aqueous solution. In a carbon nanotube/PEO105-PPO70-PEO105 (poloxamer 407) aqueous solution, the amphiphilic poloxamer 407 adsorbs onto the carbon nanotube surfaces and self-assembles into continuous layers, driven by intermolecular interactions between constituent molecules. The addition of 5-methylsalicylic acid changes the self-assembled structure from spherical-micellar to a cylindrical morphology. The fabricated poloxamer 407/carbon nanotube hybrid particles exhibit thermo-responsive structural features so that the density and thickness of poloxamer 407 layers are also reversibly controllable by varying temperature. The detailed structural properties of the poloxamer 407/carbon nanotube particles in suspension can be characterized by small-angle neutron scattering experiments and model fit analyses. The distinct curve shapes of the scattering intensities depending on temperature control or addition of aromatic additives are well described by a modified core-shell cylinder model consisting of a carbon nanotube core cylinder, a hydrophobic shell, and a hydrated polymer layer. This method can provide a simple but efficient way for the fabrication and in-situ characterization of carbon nanotube-based nano particles with a structure-tunable encapsulation.
Biology and Soft Matter Division, Neutron Science Directorate, Oak Ridge National Laboratory.
Youngkyu
Y
Han
Center for Nanophase Materials Sciences, Oak Ridge National Laboratory; Department of Polymer Science and Engineering, Pusan National University.
Suk-Kyun
SK
Ahn
Biology and Soft Matter Division, Neutron Science Directorate, Oak Ridge National Laboratory; Jülich Center for Neutron Science, Forschungszentrum Jülich.
Zhe
Z
Zhang
Biology and Soft Matter Division, Neutron Science Directorate, Oak Ridge National Laboratory.
Gregory S
GS
Smith
Biology and Soft Matter Division, Neutron Science Directorate, Oak Ridge National Laboratory; doc1@ornl.gov.
Changwoo
C
Do
D008823:Micelles; D037742:Nanotubes, Carbon; D020442:Poloxamer; D011108:Polymers; D053838:Scattering, Small Angle
D008823:Micelles; D037742:Nanotubes, Carbon; D011108:Polymers; D020442:Poloxamer