Arrangement of Conductive Rod Nanobrushes via Conductive鈥揇ielectric鈥揅onductive Sandwiched Single Crystals of Poly(ethylene glycol) and Polyaniline Block Copolymers

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• 作者：Maryam Nazari ; Samira Agbolaghi ; Saleheh Abbaspoor ; Homa Gheybi ; Farhang Abbasi
• 刊名：Macromolecules
• 出版年：2015
• 出版时间：December 22, 2015
• 年：2015
• 卷：48
• 期：24
• 页码：8947-8957
• 全文大小：703K
• ISSN：1520-5835

文摘

Conductive rod nanobrushes of polyaniline (PANI) were developed via the growth of conductive鈥揹ielectric鈥揷onductive sandwiched single crystals obtained from poly(ethylene glycol) (PEG₅₀₀₀)-b-PANI_n, PANI_n-b-PEG₆₀₀₀-b-PANI_n, and PANI_n-b-PEG₃₅₀₀₀-b-PANI_n block copolymers synthesized by interfacial polymerization fostering two different oxidants (ammonium peroxydisulfate (APS) as a weaker and potassium hydrogen biiodate (PHD) as a stronger oxidant). Based on the dispersity of the diameter of the PANI nanofibers and the various molecular weights of PEG substrates, two distinct morphologies were detected, i.e., matrix鈥揹ispersed morphology for PANI_n-b-PEG₃₅₀₀₀-b-PANI_n and dispersed鈥揹ispersed morphology for PANI_n-b-PEG₆₀₀₀-b-PANI_n and PEG₅₀₀₀-b-PANI_n single crystals. In matrix鈥揹ispersed single crystals, through an elevated crystallization temperature (T_c), a convergence occurred between the heights of matrix (partly stretched PANIs) and disperses (fully stretched PANIs). Because of their higher conductivity (e.g., 3 vs 10^鈥? S/cm for copolymers and 84 vs 8 脳 10^鈥? S/cm for corresponding homopolymers), the variation in height between the matrix and disperses was lower in PHD-synthesized PANI nanofibers (e.g., height variance of 2 nm for PHD-synthesized PANI₁₈₀ vs 57 nm for APS-synthesized PANI₁₇₅ at T_c = 38 掳C). The diameter of the dispersed PANI was inversely proportional to the crystallization temperature and was directly proportional to the PANI repeating units. Although in PEG₃₅₀₀₀-based systems PANI-dispersed diameters of up to 58 nm were detected in PANI₁₀₉-b-PEG₇₉₅-b-PANI₁₀₉ single crystals at T_c = 18 掳C due to a scarcity in the provided surface area, the maximum diameters included in PEG₆₀₀₀ and PEG₅₀₀₀ single crystals were 9 and 7 nm, respectively. In dispersed鈥揹ispersed morphologies, having extended conformation of PANI brushes on PEG₅₀₀₀ and PEG₆₀₀₀ substrates, their substrate thickness did not vary by the lengthening of the PANI brushes, and the only effect oxidant had in these systems was on the population of grown single crystals; that is, the weaker the oxidant, the larger the population.