Dependence of the dispersion behavior of [60]fullerene in aqueous media on the chain length of poly(N-isopropylacrylamide) as a dispersing agent

作者：Uchida Katsumi; Tamura Atsushi; Fukushima Naoyuki; Yajima Hirofumi^*

来源：Colloid and Polymer Science, 2011, 289(1): 73-78.

DOI：10.1007/s00396-010-2317-4

• [60]Fullerene
• Poly(N-isopropylacrylamide)
• Complex
• Dispersion
• Reversibility

We have investigated the effect of the chain length of temperature-sensitive poly(N-isopropylacrylamide) (PIPAAm) on the dispersion of [60]fullerene (C(60)) in aqueous media through an interaction between PIPAAm and C(60) below the lower critical solution temperature (LCST) of PIPAAm. UV-vis absorption spectral measurements showed that the saturated amount of the dispersed C(60) increased in proportion to the chain length of the PIPAAm. Additionally, an absorption band at around 430 nm was observed in the dispersed C(60) solution and was assigned to a C(60)/PIPAAm complex. The complex formed an amorphous molecular assembly between C(60) molecules and PIPAAm chains, the structure of which was confirmed in a transmission electron microscopy image. Dynamic light scattering measurements indicated that the particle size of the C(60)/PIPAAm complex increased with the chain length of the PIPAAm. From electrophoretic laser light scattering measurements, the zeta potential of the C(60)/PIPAAm complex was found to be shifted from a negative value to zero with an increase in the chain length of PIPAAm. Longer PIPAAm chains, however, gave rise to a higher dispersion stability of the complex. Similar to the dispersion behavior of PIPAAm-C(60) conjugates in aqueous solutions, the aqueous C(60) dispersion with PIPAAm exhibited rapid, and reversible dispersion-aggregation changes in response to temperature alternation across the LCST.

• 出版日期2011-1