Smart Microcapsules Encapsulating Reconfigurable Carbon Nanotube Cores

• Published in: Advanced functional materials Vol. 20; no. 5; pp. 820 - 825
• Main Authors: Choi, Won San, Yang, Hye Min, Koo, Hye Young, Lee, Ha-Jin, Lee, Young Boo, Bae, Tae Sung, Jeon, Il Cheol
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 09.03.2010; WILEY‐VCH Verlag
• Subjects: carbon nanotubes; heavy metal ion removal; hierarchical structures; iron oxide
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.200901739

The encapsulation of carbon nanotubes (CNTs) to form a reconfigurable conglomerate within iron oxide microcapsules is demonstrated. The individual CNTs conglomerate and form a core inside the capsule upon exposure to high temperature, while they scatter when subjected to mild sonication at low pH. The assembly/disassembly of CNTs within the capsule was reversible and could be repeated by alternate heating and sonication. Also, the fabrication protocol could be used for the generation of various multifunctional hollow structures. To test the feasibility of using the capsules in real applications, the capacity of the capsules as a heavy metal ion remover was explored. The resulting capsules showed an excellent ability to remove lead and chromium ions. In addition, desorption of the metal ions adsorbed on the CNTs could be induced by exposure to low pH. Thus, encapsulated CNTs might be a recyclable, environmentally friendly agent for the removal of heavy metal ions. Heavy metal ion removal is demonstrated using carbon nanotubes (CNTs) surrounded by iron oxide microscapsules. The CNTs conglomerate and form a core inside the capsule upon exposure to high temperature, while they scatter when they are subjected to mild sonication under low pH. This assembly/disassembly of the CNTs within the capsule is reversible and can be repeated by alternate heating and sonication. These hierarchical structures can capture lead and chromium ions, which can later be desorbed by exposure to low pH conditions.