Influence of polar groups on the wetting properties of vertically aligned multiwalled carbon nanotube surfaces

Author(s)

Ramos, S. C. ^{[1, 2]} ; Lobo, A. O. ^[3] ; de Vasconcelos, G. ^[4] ; Antunes, E. F. ^{[5, 1]} ; Trava-Airoldi, V. J. ^[1] ; Corat, E. J. ^[1]

Affiliation

^[1] Inst Nacl Pesquisas Espaciais, Lab Assoc Sensores & Mat, BR-12227010 Sao Jose Dos Campos, SP - Brazil

^[2] Univ Estado Bahia, UNEB, Dept Ciencias, BR-46400000 Caetite, BA - Brazil

^[3] Univ Vale Paraiba, UniVaP, Inst Pesquisa & Desenvolvimento, IP&D, Lab Nanatecnol Biomed, BR-12244000 Sao Jose Dos Campos, SP - Brazil

^[4] Inst Estudos Avancados, IEAv, BR-12228001 Sao Jose Dos Campos, SP - Brazil

^[5] ITA, BR-12228900 Sao Jose Dos Campos, SP - Brazil

• Document type: Journal article
• Source: THEORETICAL CHEMISTRY ACCOUNTS; v. 130, n. 4-6, p. 1061-1069, DEC 2011.
• Web of Science Citations: 10

Abstract

In this work, we have studied superhydrophilic and superhydrophobic transitions on the vertically aligned multiwalled carbon nanotube (VACNT) surfaces. As-grown, the VACNT surfaces were superhydrophobic. Pure oxygen plasma etching modified the VACNT surfaces to generate superhydrophilic behavior. Irradiating the superhydrophilic VACNT surfaces with a CO(2) laser (up to 50 kW cm(-2)) restored the superhydrophobicity to a level that depended on the laser intensity. Contact angle and surface energy measurements by the sessile drop method were used to examine the VACNT surface wetting. X-ray photoelectron spectroscopy (XPS) showed heavy grafting of the oxygen groups onto the VACNT surfaces after oxygen plasma etching and their gradual removal, which also depended on the CO(2) laser intensity. These results show the great influence of polar groups on the wetting behavior, with a strong correlation between the polar part of the surface energy and the oxygen content on the VACNT surfaces. In addition, the CO(2) laser treatment created an interesting cage-like structure that may be responsible for the permanent superhydrophobic behavior observed on these samples. (AU)

• FAPESP's process: 07/00013-4 - New materials, studies and applications of CVD diamond, diamond-like-carbon (DLC) and nanostructured carbon obtained by chemical vapor deposition
• Grantee: Evaldo Jose Corat
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 08/11642-5 - Development of structures based on carbon nanotubes, bioresorbable polymers and carbon fibers for studies with regenerative cells and hematopoietic stem cells
• Grantee: Anderson de Oliveira Lobo
• Support Opportunities: Scholarships in Brazil - Doctorate