Universality and Percolation in Biodegradable Poly(ε-caprolactone)/Multiwalled Carbon Nanotube Nanocomposites from Broad Band Alternating and Direct Current Conductivity at Various Temperatures
| Autor: | Estrella Laredo, Alejandro J. Müller, Philippe Dubois, M. Grimau, Jesús R. Marval, Benoit Ruelle, Alfredo Bello, María Luisa Arnal |
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| Rok vydání: | 2011 |
| Předmět: |
Nanotube
Nanocomposite Materials science Polymers and Plastics Organic Chemistry Analytical chemistry Concentration effect Nanotechnology Carbon nanotube Conductivity Atmospheric temperature range law.invention Inorganic Chemistry Percolation theory law Electrical resistivity and conductivity Materials Chemistry |
| Zdroj: | Macromolecules. 44:2819-2828 |
| ISSN: | 1520-5835 0024-9297 |
| DOI: | 10.1021/ma102598h |
| Popis: | Dc and ac conductivities in a broad angular frequency, 2π × 10−3 s−1 < ω < 2π × 107 s−1, and temperature range, 133 K < T < 323 K, were measured in poly(e-caprolactone)/multiwalled carbon nanotube nanocomposites as a function of weight concentration (0 wt % ≤ p ≤ 3 wt %) . The universal dynamic response was observed at low p values, and the parameters were adjusted by working in several domains. Scaling laws predicted by the variation of dc conductivity as a function of p or characteristic frequency in percolation theory were followed and showed the formation of a 3D percolative cluster at concentration values as low as 0.3 wt %. The existence of tunneling conduction was proved, and its independence on temperature indicates that we are in the presence of a conventional tunnel effect among nanoparticles not yet in physical contact, through energy barriers made by the polymer chains. All these combined facts allowed construction of a master curve evidencing the time−temperature−composition superposition exi... |
| Databáze: | OpenAIRE |
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