Poly(3-hexylthiophene) Nanotube Array Surfaces with Tunable Wetting and Contact Thermal Energy Transport

Abstract

Solution casting using a sacrificial template is a simple technique to fabricate vertical arrays of polymer nanotubes. However, because of their close proximity and high aspect ratios, large capillary forces cause nanotubes to cluster as the array dries; researchers often use special drying techniques to avoid this clustering. Here, we exploit the clustering of regioregular poly(3-hexylthiophene) (rr-P3HT) nanotubes in a unique template etching process to create surfaces that exhibit tunable wetting and contact thermal energy transport. Vertical arrays of rr-P3HT nanotubes are cast from solution in nanoscale alumina templates, and a solution etching process is used to partially release the nanotubes from the template. The clustering of rr-P3HT nanotube tips upon template etching produces hierarchical surface structuring with a distinct pattern of interconnected ridges, and the spacing between the ridges increases with increased template etch times. These changes in morphology cause the water contact angle to increase from 141° to 168° as the etch time is increased from 4 to 12 min. When assembled into an interface, the morphological changes cause the thermal contact resistance of the vertical rr-P3HT nanotube arrays to increase linearly at a rate of approximately 6 mm(2)·K/W per 2 min etch interval (after 6 min of etching is surpassed). The effective thermal conductivity of the rr-P3HT nanotube arrays is 1 ± 0.2 W/mK independent of the etch time, which is approximately 5 times higher than the bulk rr-P3HT film value.

Hydrophobicity of Highly Ordered Nanorod Polycrystalline Nickel and Silver Surfaces

“…The surface energy decreased with increasing AR. This hydrophobicity boosting phenomenon could be explained also by elastocapillary coalescence [24]. High hydrophobicity of prepared nanorod metal array surfaces enhanced by elastocapillary coalescence creates unacceptable environment for cell adhesion and spreading as it is mentioned in our former publication [18].…”

Device Fabrication Based on Oxidative Chemical Vapor Deposition (oCVD) Synthesis of Conducting Polymers and Related Conjugated Organic Materials

“…Phonon transport would be extremely influenced by the random curvature of polymer chains as well as series of bends along polymer chains due to the plane wave nature of phonons . The thermal conductivity in polymers would be enhanced by alignment of molecular chains through methods such as mechanical stretching, nanoscale templating, and surface grafting . The elongated sections of chains in crystalline (semicrystalline) polymers can serve as efficient heat conductors along the chain axis due to the stiff covalent bonding.…”

One-Dimensional Nanostructure Engineering of Conducting Polymers for Thermoelectric Applications

“…It has been reported that continuous long nanofibers from P3AT can be produced by electrospinning method, [24,51,52] while the shorter P3AT nanofibers are mostly formed via self-assembly in solution with good crystallinity owing to strong interactions along their longitudinal axis [53][54][55][56]. Other approaches, such as vapor-assisted imprinting [57], electrochemical synthesis [58,59] and solution casting method [60,61] using sacrificial templates have also been employed to prepare P3AT nanowires or nanotubes for diverse applications.…”