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Controlling the morphological, structural, and optical properties of one-dimensional PCDTBT nanotubes by template wetting.

Bakar NA, Supangat A, Sulaiman K - Nanoscale Res Lett (2014)

Bottom Line: In this study, the synthesis of poly [N-9'-heptadecanyl-2, 7-carbazole-alt-5, 5-(4', 7'-di-2-thienyl-2', 1', 3'-benzothiadiazole)] (PCDTBT) nanotubes via a templating method is reported.PCDTBT nanotubes were successfully grown by immersing the porous alumina template into 15 mg/ml of solution concentration for 2- and 24-h periods and annealed at 50°C.Nanotubes that are formed between 2 and 24 h of infiltration show enhancement in absorption, photoluminescence, and shift in Raman peak if compared to their thin films.

View Article: PubMed Central - HTML - PubMed

Affiliation: Low Dimensional Materials Research Centre, Department of Physics, University of Malaya, Kuala Lumpur 50603, Malaysia.

ABSTRACT
In this study, the synthesis of poly [N-9'-heptadecanyl-2, 7-carbazole-alt-5, 5-(4', 7'-di-2-thienyl-2', 1', 3'-benzothiadiazole)] (PCDTBT) nanotubes via a templating method is reported. PCDTBT nanotubes were successfully grown by immersing the porous alumina template into 15 mg/ml of solution concentration for 2- and 24-h periods and annealed at 50°C. Changes in morphological and optical properties between nanotubes of different infiltration times (2 and 24 h) as well as its thin films are observed. The longer infiltration time of 24 h produced nanotubes with enhanced morphological, structural, and optical properties. Nanotubes that are formed between 2 and 24 h of infiltration show enhancement in absorption, photoluminescence, and shift in Raman peak if compared to their thin films.

No MeSH data available.


Schematic illustrations on the formation of PCDTBT nanotubes. Formation of PCDTBT nanotubes due to (a) Capillary and gravitational force of PCDTBT solution inside nanopores and (b) wetting and complete filling of the nanopores. (c) Formation of convex meniscuses and (d) PCDTBT nanotubes of broken meniscuses.
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Figure 2: Schematic illustrations on the formation of PCDTBT nanotubes. Formation of PCDTBT nanotubes due to (a) Capillary and gravitational force of PCDTBT solution inside nanopores and (b) wetting and complete filling of the nanopores. (c) Formation of convex meniscuses and (d) PCDTBT nanotubes of broken meniscuses.

Mentions: The proposed formation of PCDTBT nanotubes is illustrated in Figure 2a,b,c,d. The PCDTBT solution infiltrates into the template by two wetting phenomena namely (i) capillary force (repulsion) which cause the solution to rise from the bottom of the template and (ii) with the assistance of gravity that contributes to the flow of solution from the top of the template into the nanopore (Figure 2a). When a solution is brought into contact with a substrate of high surface energy, the solution will spread and form a thin film. Once the template is immersed, the solution will infiltrate to a certain extent and cover the template's pore walls. Wetting and complete filling of the template's pore occur consecutively (Figure 2b). Wetting of pore walls occurs prior to the complete filling due to the stronger adhesive forces between the PCDTBT molecules and the pore wall surface rather than the cohesive forces. Rapid evaporation of solvent has inhibited the polymer solution from completely filling the template's pore which then produces nanotubes instead of nanorods[17]. During the evaporation of solvent, two convex meniscuses were formed. Once the weight of the solution is balanced by the surface tension, the solution will stop flowing from the top and cause saturation at the end of the flowing, which causes a convex meniscus (Figure 2c). Capillary repulsion causes the bottom part of convex meniscus to form. As shown in Figure 2d, the remaining PCDTBT nanostructures with the broken cap are obtained after the template's dissolution. Nanotubes that were formed at the upper part of the template will fall onto the other nanotubes that were formed in the bottom part of the template.FESEM and HRTEM images shown in Figure 3a,b,c,d gave evidence to the proposed formation of PCDTBT nanotubes caused by capillary and gravitational forces. Convex meniscuses can be observed at the tip of nanotubes (circle in red) with some of them are broken cap (Figure 3a,b). The closed end nanotubes are easily broken during the FESEM and TEM samples preparation due to the thin wall thickness of approximately 20 nm. The broken meniscus is supported by the HRTEM images shown in Figure 3c,d of 2 and 24 h of immersion time, respectively.


Controlling the morphological, structural, and optical properties of one-dimensional PCDTBT nanotubes by template wetting.

Bakar NA, Supangat A, Sulaiman K - Nanoscale Res Lett (2014)

Schematic illustrations on the formation of PCDTBT nanotubes. Formation of PCDTBT nanotubes due to (a) Capillary and gravitational force of PCDTBT solution inside nanopores and (b) wetting and complete filling of the nanopores. (c) Formation of convex meniscuses and (d) PCDTBT nanotubes of broken meniscuses.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 2: Schematic illustrations on the formation of PCDTBT nanotubes. Formation of PCDTBT nanotubes due to (a) Capillary and gravitational force of PCDTBT solution inside nanopores and (b) wetting and complete filling of the nanopores. (c) Formation of convex meniscuses and (d) PCDTBT nanotubes of broken meniscuses.
Mentions: The proposed formation of PCDTBT nanotubes is illustrated in Figure 2a,b,c,d. The PCDTBT solution infiltrates into the template by two wetting phenomena namely (i) capillary force (repulsion) which cause the solution to rise from the bottom of the template and (ii) with the assistance of gravity that contributes to the flow of solution from the top of the template into the nanopore (Figure 2a). When a solution is brought into contact with a substrate of high surface energy, the solution will spread and form a thin film. Once the template is immersed, the solution will infiltrate to a certain extent and cover the template's pore walls. Wetting and complete filling of the template's pore occur consecutively (Figure 2b). Wetting of pore walls occurs prior to the complete filling due to the stronger adhesive forces between the PCDTBT molecules and the pore wall surface rather than the cohesive forces. Rapid evaporation of solvent has inhibited the polymer solution from completely filling the template's pore which then produces nanotubes instead of nanorods[17]. During the evaporation of solvent, two convex meniscuses were formed. Once the weight of the solution is balanced by the surface tension, the solution will stop flowing from the top and cause saturation at the end of the flowing, which causes a convex meniscus (Figure 2c). Capillary repulsion causes the bottom part of convex meniscus to form. As shown in Figure 2d, the remaining PCDTBT nanostructures with the broken cap are obtained after the template's dissolution. Nanotubes that were formed at the upper part of the template will fall onto the other nanotubes that were formed in the bottom part of the template.FESEM and HRTEM images shown in Figure 3a,b,c,d gave evidence to the proposed formation of PCDTBT nanotubes caused by capillary and gravitational forces. Convex meniscuses can be observed at the tip of nanotubes (circle in red) with some of them are broken cap (Figure 3a,b). The closed end nanotubes are easily broken during the FESEM and TEM samples preparation due to the thin wall thickness of approximately 20 nm. The broken meniscus is supported by the HRTEM images shown in Figure 3c,d of 2 and 24 h of immersion time, respectively.

Bottom Line: In this study, the synthesis of poly [N-9'-heptadecanyl-2, 7-carbazole-alt-5, 5-(4', 7'-di-2-thienyl-2', 1', 3'-benzothiadiazole)] (PCDTBT) nanotubes via a templating method is reported.PCDTBT nanotubes were successfully grown by immersing the porous alumina template into 15 mg/ml of solution concentration for 2- and 24-h periods and annealed at 50°C.Nanotubes that are formed between 2 and 24 h of infiltration show enhancement in absorption, photoluminescence, and shift in Raman peak if compared to their thin films.

View Article: PubMed Central - HTML - PubMed

Affiliation: Low Dimensional Materials Research Centre, Department of Physics, University of Malaya, Kuala Lumpur 50603, Malaysia.

ABSTRACT
In this study, the synthesis of poly [N-9'-heptadecanyl-2, 7-carbazole-alt-5, 5-(4', 7'-di-2-thienyl-2', 1', 3'-benzothiadiazole)] (PCDTBT) nanotubes via a templating method is reported. PCDTBT nanotubes were successfully grown by immersing the porous alumina template into 15 mg/ml of solution concentration for 2- and 24-h periods and annealed at 50°C. Changes in morphological and optical properties between nanotubes of different infiltration times (2 and 24 h) as well as its thin films are observed. The longer infiltration time of 24 h produced nanotubes with enhanced morphological, structural, and optical properties. Nanotubes that are formed between 2 and 24 h of infiltration show enhancement in absorption, photoluminescence, and shift in Raman peak if compared to their thin films.

No MeSH data available.