Directed crystallization of CuSO4·5H2O onto carbon nanotube microarchitectures

Abstract

An assembly technique based on crystallization of thin CuSO 4·5H2O microcrystals from salt solution onto patterned three-dimensional (3D) multiwalled carbon nanotube (MWNT) platform was developed. The vertically aligned MWNT arrays served as nucleation sites for the formation of microstructured CuSO4·5H2O crystals. In the presence of MWNTs, the CuSO4·5H2O crystal exhibited preferential crystallization in the (2̄22) orientation. Sculpting the MWNT platforms using a focused laser beam, as well as utilizing capillary forces that occurred during the drying process of the salt solution, a variety of 3D MWNT-microcrystal hybrid systems were created. In addition to the 3D MWNT platform created by focused laser beam pruning, we have also achieved assembly of the microcrystals onto MWNT array with patterned hydrophilic and hydrophobic regions. Such chemical modifications of the MWNT surface were achieved without introducing any physical destruction to the MWNT arrays. As such, two-dimensional template-directed assembly of crystals onto the hydrophilic regions on the MWNT surface was realized. © 2011 American Chemical Society.