Porous Anodic Aluminum Oxide Template Research Articles

Novel CdSe nanorods/porous anodic alumina nanocomposite-based ethanol sensor: sensitivity enhancement by visible light illumination

In this present work, l-cysteine capped CdSe nanoparticles synthesized by a chemical route process were successfully embedded into porous anodic alumina (PAA) template via chemical bath deposition method. CdSe nanorods (NRs) were grown vertically on the PAA template via thermal annealing process at 350 °C under nitrogen. The morphological, structural, and optical properties of the prepared PAA and CdSe/PAA films were investigated in detail. The scanning electron microscopy exhibited the formation of CdSe NRs array with a pyramidal ends onto all sides of PAA matrix. Energy dispersive X-ray analysis confirmed that the prepared CdSe NRs/PAA are made of cadmium, selenium, and alumina materials. X-ray diffraction study revealed that the CdSe layer exhibit a hexagonal structure and the average crystallite size at about 9 nm. PL measurements showed green and bleu emissions peaks located at 2.05 eV and 2.7 that originate from the luminescent CdSe NRs and the oxygen defficiency centers formed in the PAA, respectively. CdSe NRs film on the PAA template was fabricated and employed as gas sensor for the detection of ethanol under visible-light illumination for 25–300 ppm at the optimum working temperature of 200 °C. Light illumination strongly enhance the sensor sensitivity. This effect has been discussed in term of light-matter interaction on the CdSe NRs surface. More hole are probably created which increase the conductance of the sensor and significantly improved the gas response

(Invited) Synthesis of Ordered Semiconductor Nanostructures for Energy Conversion Using Anodic Porous Alumina

Efficient synthesis of the ordered nanostructures of semiconductors is important issue to be solved for the preparation of the photo-energy conversion systems with high efficiency [1]. For the effective preparation of the ordered nanostructures of semiconductors, the use of the naturally occurring ordered nanomaterials is promising for the synthesis due to its capability of the preparation of ordered nanostructures with high efficiency. Among them, anodic porous alumina, which is formed by anodization of Al in acidic electrolyte, is one of promising material due to ist precisely controllable geometrical nanostructures [2]. In the present report, the synthesis of the ordered nanostructures of semiconductors using anodic porous alumina templates will be described. The template synthesis using highly ordered anodic porous alumina allows the preparation of ordered nanostructures of the semiconductors. In addition, the application of the highly ordered anodic porous alumina with reduced hole intervals (~25 nm) and hole sizes (~10 nm) prepared under the low voltage anodization [3] generated the ordered structures of semiconductors with small dimensions. In the experiment, semiconductor (ZnO [4,5], CdS) nanorod arrays were prepared by electrochemical or hydrothermal synthesis of semiconductors using anodic porous alumina templates. The geometrical structure of the obtained nanorod arrays of semiconductors could be precisely controlled based on the ordered structures of anodic porous alumna. The synthesis of the nanorod arrays on the conducting substrates (ITO etc.) could provide the current collection electrodes with large surface area. The present process will be used for the preparation of nanostructures of semiconductors, which are required for the preparation of various kinds of photoenergy conversion systems with high efficiency, such as organic photovoltaic solar cells [6]. 1. T. Shinagawa, S. Watase, M. Izaki, Cryst. Growth Des., 11, 5533 (2011). 2. H. Masuda and K. Fukuda, Science, 268, 1466 (1995). 3. H. Masuda, K. Takenaka, T. Ishii, K. Nishio, Jpn. J. Appl. Phys., 45, L1165 (2006). 4. M. Izaki, T. Omi, Appl. Phys. Lett., 98, 2439 (1996). 5. T. Özdal, R. Taktakoğlu, H. Özdamar, M. Esen, D. K. Takҫi, H. Kavak, Thin Solid Films, 592, 143 (2015). 6. B. Kippelen, J.-L. Brédas, Energy Environ. Sci., 2, 251 (2009).

Broadband light absorber based on porous alumina structure covered with ultrathin iridium film

In this letter, we propose a broadband absorber with high efficiency by an atomic layer depositing nanometer iridium (Ir) film onto a porous anodic alumina (PAA) template. The average absorption is able to achieve as high as 93.4% from 400 to 1100 nm and the absorption efficiency can reach up to 96.8% for the improved structure of the quadrangular frustum pyramid array. Not only the hexagonal latticed structures of the PAA template but also many similar structures based on gratings or holes with the square latticed or other latticed mode can realize the broadband high absorption efficiency. The light absorbed within the Ir/Glass interface and the sidewalls of PAA by the light funneling effect both contribute to the broadband absorption with high efficiency. This absorber, described in this paper, can be manufactured with a low-cost and large-area manner and has potential applications in fields of light harvesting, imaging, etc.

Enhanced Absorption in Organic Thin-Films from Imprinted Concave Nanostructures

In this work, a rapid, replicable method for imprinting concave nanostructures to be used as functional light-trapping nanostructures in organic thin-films is presented. Porous anodic alumina templates were fabricated both by anodization of thick Al foils and by anodization of submicrometer thin Al films evaporated via e-beam evaporation on Si substrates. The template formation leads to natural patterning of the underlying Al layers that are used as rigid masters for stamp fabrication, after selective etching of the porous anodic alumina. PDMS stamps were made after replicating the Al concave patterns and used for imprinting of spin coated photoresist on glass substrates. We have investigated semi-periodic and aperiodic imprinted large concave patterns fabricated from rigid masters after anodization of Al in H3PO4. We show that metal covered imprinted concaves show enhancement in absorption that is attributed to field enhancement and diffuse scattering, leading to efficient light trapping for a selected active layer material (P3HT:PCBM).DOI: http://dx.doi.org/10.5755/j01.ms.23.1.14188

Removal of Cr (VI) from Industrial Waste Water by Iron Nanowires Synthesized via Porous Anodic Aluminum Oxide Template

Iron nanowires were successfully prepared by electrodeposition method via ordered nanoporous anodized aluminum oxide (AAO) template since the technique is simple and cost-effective. The preparation of nano porous anodized aluminum template involved annealing and electropolishing as a pretreatment. It has been found that regularity of pores increases after the pre-treatment. The average surface roughness factor (Ra) was measured with the help of portable surface roughness tester. Pore diameter, pore density, porosity and uniformity of pores was determined with the help of image-J software. Morphology of nanoporous oxide and iron nanowires was confirmed with FE-SEM and EDS analysis. The pore diameter of template ranged from 105 nm to 120 nm. The fabricated nano wires were found to have length of 643 nm and diameter of 103 nm with unique environmental applications.

Effect of Template on the Structure of Carbon Nanotubes Grown by Catalytic Chemical Vapor Deposition Method

Carbon nanotubes (CNTs) have been synthesized on an anodized aluminum oxide (AAO) template with acetylene by using catalytic chemical vapor deposition (CVD). It was found that the structure of CNTs can be mostly depends on the quality of the catalyst deposition in the pores of AAO template. Straight CNTs were observed when Ni catalyst deposited only in the bottom of holes as nanoparticles, but when Ni catalyst fulfilled the holes of AAO template as nanowires (NWs), coiled CNTs observed. The characterization of as-prepared materials was examined by SEM and Raman spectroscopy. In addition, it is realized that the nanostructure of the AAO template strongly affected the properties of as-grown CNTs. In the other word, based on the obtained results the diameter and pitch of coiled CNTs tightly depend on the size of metallic catalyst and in the results it depend on the pore diameter of AAO template.

A template/electrochemical deposition method for fabricating silver nanorod arrays based on porous anodic alumina

A template/electrochemical deposition method for fabricating silver nanorod arrays based on porous anodic alumina was presented. The barrier layer of porous anodic alumina templates was thinned by step-by-step voltage decrement method. Subsequently, silver ions were reduced into the channels of porous anodic alumina templates by electrochemical deposition method. Electrochemical impedance spectroscopy was utilized for analyzing the thickness of barrier layer of porous anodic alumina templates; the elementary composition and the size of silver nanorod arrays were characterized by X-ray diffraction and field-emission scanning electron microscope, respectively. Experimental results showed that the thickness of barrier layer of porous anodic alumina was suitable for alternating current electrochemical deposition, when anodizing potential was decreased to 70 V and widening time of porous anodic alumina in H3PO4 solution is 80 min. And the silver particles could be deposited into the channels of porous anodic alumina templates at 11 V, 13 V, and 15 V. Different sizes of silver nanorod arrays were obtained by controlling the deposition time. The average diameter of silver nanorod is in the range from 346 nm to 351 nm which is almost consistent with the pore diameter of porous anodic alumina templates (367 nm). The uniform silver nanorod arrays have a considerable potential in the flexible and wearable electronic devices, optics, solar cell, the catalytical electrode, and so on.

Synthesis of highly ordered carbon nanotubes/nanoporous anodic alumina composite membrane and potential application in heavy metal ions removal from industrial wastewater

Highly ordered carbon nanotubes arrays produced within pores of nano porous anodic alumina template via chemical vapor deposition method and pyrolysis of ethylene gas.Effective removal of copper (II) and cadmium (II) from simulated industrial waste water was performed with the nanometer scale pores in composite membrane of highly ordered carbon nanotubes. Our results shows that hydrophobic inner walls of carbon nanotubes have capability to adsorb heavy metal ions. Water pH effect on removal efficiency of composite membrane in was also investigated and the results showed that adsorption percentage of ions is enhancing with increasing pH of the solutions.

Flexible anodized aluminum oxide membranes with customizable back contact materials

Anodized aluminum oxide (AAO) membranes were fabricated using flexible substrate/carrier material. This method facilitates the use of AAO templates with many different materials as substrates that are otherwise incompatible with most anodization techniques. Thin titanium (Ti) and tungsten (W) layers were employed as interlayer materials. Titanium enhances adhesion. Tungsten not only helps eliminate the barrier layer but also plays a critical role in enabling the use of flexible substrates. The resulting flexible templates provide new, exciting opportunities in photovoltaic and other device applications. CuInSe2 nanowires were electrochemically deposited into porous AAO templates with molybdenum (Mo) as the back contact material. The feasibility of using any material to form a contact with semiconductor nanowires has been demonstrated for the first time enabling new avenues in photovoltaic applications.

Fabrication of PVDF hierarchical fibrillar structures using electrospinning for dry-adhesive applications

We report the fabrication of hierarchical poly(vinylidene fluoride) (PVDF) fibrous structures using a unique fabrication technique based on electrospinning. Electrospinning was used to fabricate aligned PVDF fibrous membranes. These membranes were then brought in contact with anodized aluminum oxide (AAO) template and then heat-treated above the glass transition temperature (T g) of the polymer to assist the flow of polymer within the cylindrical pores of AAO template. Scanning electron microscopy images confirmed that this approach lead to the growth of nanopillars on the surface of PVDF fibers. Nanoindenter was used to measure the pull-off force that was required to completely detach the indenter from the samples. To investigate the effect of hierarchy, pull-off force required to detach the indenter from neat PVDF fibers was determined and compared with the pull-off force recorded for hierarchical fibers. The effect of indentation depth was also investigated on both PVDF fibers and PVDF fiber with nanopillars. Significant pull-off force recorded indicates that these PVDF hierarchical fibrous structures can be potentially used for dry-adhesive applications.

Enhanced Elastic Modulus of Regenerated Silk Fibroin by Geometric Confinement in Anodized Aluminum Oxide Templates

Geometric confinement is a promising method for the reconstruction of silk fibroin to form diversified structures with excellent mechanical properties. To accomplish geometric confinement, a water vapor assistant embossing process is used with porous anodic aluminum oxide templates, yielding silk fibroin nanopillars with diameters ranging from 40 nm to 130 nm. The elastic modulus of the regenerated silk fibroin nanopillars is investigated with atomic force microscopy nanoindentation analysis. Compared to films with the same treatment conditions, geometric confinement provided a twofold increase in elastic modulus in embossed silk fibroin nanopillars, indicating that β-sheet crystal ordering occurred during the water vapor assistant embossing process. These results demonstrate the feasibility and mechanical property enhancement of the embossing method to fabricate silk nanostructures, and will be useful in designing miniaturized devices.

Fabrication of SnO2-TiO2 core-shell nanopillar-array films for enhanced photocatalytic activity

Immobilized or deposited thin film TiO2 photocatalysts are suffering from a low photocatalytic activity due to either a low photon absorption efficiency or a high carrier recombination rate. Here we demonstrate that the photocatalytic activity of TiO2 can be effectively improved by the SnO2-TiO2 core-shell nanopillar-array structure which combines the benefits of SnO2/TiO2 heterojunction and high reaction surface area. The SnO2-TiO2 core-shell nanopillar-array films were fabricated using atomic layer deposition and dry etching techniques via barrier-free porous anodic alumina templates. The photocatalytic activity of the prepared films was evaluated by methylene blue (MB) bleaching under 352nm UV light irradiation. The results show that the photocatalytic activity of TiO2 film was 45% improved by introducing a SnO2 film between TiO2 and ITO glass substrate and was 300% improved by using the SnO2-TiO2 core-shell nanopillar-array structure. The 45% improvement by the SnO2 interlayer is attributed to the SnO2/TiO2 heterojunction which separates the photogenerated electron-hole pairs in TiO2 for MB degradation, and the high photocatalytic activity of the SnO2-TiO2 core-shell nanopillar-array films is attributed to the three dimensional SnO2/TiO2 heterojunction which owns both the carrier separation ability and the high photocatalytic reaction surface area.

Developing high coercivity in large diameter cobalt nanowire arrays

Regardless of the synthetic method, developing high magnetic coercivity in ferromagnetic nanowires (NWs) with large diameters has been a challenge over the past two decades. Here, we report on the synthesis of highly coercive cobalt NW arrays with diameters of 65 and 80 nm, which are embedded in porous anodic alumina templates with high-aspect-ratio pores. Using a modified electrochemical deposition method enabled us to reach room temperature coercivity and remanent ratio up to 3000 Oe and 0.70, respectively, for highly crystalline as-synthesized hcp cobalt NW arrays with a length of 8 μm. The first-order reversal curve (FORC) analysis showed the presence of both soft and hard magnetic phases along the length of the resulting NWs. To develop higher coercive fields, the length of the NWs was then gradually reduced in order from bottom to top, thereby reaching NW sections governed by the hard phase. Consequently, this resulted in record high coercivities of 4200 and 3850 Oe at NW diameters of 65 and 80 nm, respectively. In this case, the FORC diagrams confirmed a significant reduction in interactions between the magnetic phases of the remaining sections of NWs. At this stage, x-ray diffraction (XRD) and dark-field transmission electron microscopy analyses indicated the formation of highly crystalline bamboo-like sections along the [0 0 2] direction during a progressive pulse-controlled electrochemical growth of NW arrays under optimized parameters. Our results both provide new insights into the growth process, crystalline characteristics and magnetic phases along the length of large diameter NW arrays and, furthermore, develop the performance of pure 3d transition magnetic NWs.

A Comparative Study of Anodic Aluminum Oxide Preparation for Synthesis of Nanomaterials

A template-based synthesis of nanomaterials is one of the most simple and low-cost fabricating way. The template-assisted method, which employs porous anodic aluminum oxide (AAO) templates, allows for a precise control of the morphology and dimensions of deposited nanowires [1, 2]. Nanoporous Al2O3 can be prepared by a two-step anodization of aluminum in acidic electrolytes. During the anodization, Al foil [2] or Al film sputtered on conducting substrates [3] is subjected to anodic oxidation. The anodization of Al foil results in the Al2O3/Al substrate, which is not suitable to carry out a direct electrodeposition into the pores, due to the presence of the non-conductive oxide barrier layer at the oxide/metal interface. To enable a direct electrodeposition in the Al2O3/Al substrate, the barrier layer at the pore bottom has to be removed. There are two basic methods used for the removal of the barrier layer: wet chemical etching [1, 2] and electrochemical [4–8]. The first one, the wet chemical etching requires additional steps, which include: dissolving the aluminum layer remaining after anodization of the Al foil, pore opening and widening in a phosphoric acid solution to obtain a through-hole membrane, and the sputter deposition of the conductive metal layer that serves as a working electrode during electrodeposition. Drawbacks of this method are: the use of harmful chemicals (HgCl2, CuCl2) [2] or concentrated acid solutions (H3PO4, HCl) [1, 2], and multi-stage process (loss of the material at each stage). The alternative method is based on the electrochemical reduction of the barrier layer. Due to the fact that the thickness of the barrier layer depends on the anodizing potential, a gradual decrease in the applied potential leads to a significant reduction of the barrier layer thickness. As a result of this treatment we obtain AAO, with dendritic channels with a very thin barrier layer at the pore bottoms. Such a structure allows to conduct the direct electrodeposition on the aluminum substrate without any additional steps. An important advantage of this method is the fact that the potential reduction is carried out in the same electrolyte in which the anodization was realized. Therefore, the potential reduction can be performed immediately after the anodizing process. On the other hand, there is a new electrochemical method developed by Lira and Paterson [7] for AAO detachment from the aluminum substrate. It was found that a large voltage pulse applied to the sample results in simultaneous membrane detachment and pore opening. The voltage detachment method has significant advantages over the typically used chemical etching, e.g., it is faster, and environmental friendly. As-obtained AAO membranes are suitable for electrodeposition of metallic nanostructures. Herein, we report on investigation of electrochemical methods for the AAO membrane preparation and their optimization toward further metallic nanostructure deposition. Highly ordered nanoporous AAO templates were fabricated by a two-step self-organized anodization of aluminum carried out in oxalic and sulfuric acids solutions. In the first method, the barrier layer thinning was done by applying an exponentially decreasing voltage at the end of anodization process. Depending on the function used for the reduction of the barrier layer and its thickness, the dendrite-like structures of the barrier layer were observed at the cross-sections. In the second method, a modified voltage detachment method in a mixture of HClO4 and ethanol was used. Different pulses were applied for the detachment of alumina formed in oxalic and sulfuric acids.

Ion emission properties of indium nanowires grown on anodic aluminum oxide template

Indium (In) nanowires were synthesized on self-ordered hexagonal porous anodic aluminum oxide (AAO) template by electrodepositing In2(SO4)3 in the pores of AAO template. In nanowires obtained are very straight and have uniform-diameter about 45 nm. The ion emission properties of In nanowires were investigated. The onset field of ion emission is observed at about 1.6 V/μm, which is much lower than that for a conventional liquid metal ion source (LMIS) consisting of a sharpened metal needle. The I-E curves follow nearly a linear relationship with a slope of about 6.0 μA/(V/μm), indicating a conventional ion emission phenomenon in LMIS. It is proposed that the unique geometry of nanowires may be the reason for their advantages in LMIS.

Fabrication of CdSe nanocrystals using porous anodic alumina and their optical properties

In this paper, Porous anodic alumina (PAA) template with highly ordered nanopores structure was synthesized on aluminum foils by two step anodization process. PAA template has hexagonal pores with average size between 30 and 180nm. L-cysteine (L-Cys) functionalized cadmium selenide nanocrystals (CdSe NCs) were successfully embedded inside PAA layers by simple immersion in aqueous solution. The effect of pore diameter enlargement on the microstructure of CdSe NCs/PAA films was systematically studied by FE-SEM, XRD, EDX, Raman, UV–VIS absorbance and PL analysis. FE-SEM microscopy was used to investigate the surface morphology of PAA templates before and after CdSe NCs deposition. XRD investigation demonstrates that CdSe NCs into PAA templates were cubic in nature with zinc-blende structure. Raman measurements exhibit the characteristic modes of CdSe on the PAA layers as well as the films crystallinity as function of widening pores diameter. Optical properties of deposited CdSe NCs on PAA templates have been investigated using optical absorption and PL techniques. Photoluminescence spectroscopy has been used to determine the bandgap energy and the average size of CdSe NCs deposited on PAA layer. This method involves fitting the experimental spectra, using a model based on quantum confinement of electrons in CdSe nanocrystals having spherical and cylindrical forms (Quantum Dots (QDs) and Quantum Wires (QWs)). This model allows correlation between the PL spectra and the microstructure of the CdSe/PAA. Both photoluminescence and optical absorption show that the PL peak energy and the optical absorption edge of CdSe NCs/PAA exhibit similar behavior with changes in nanostructure size. The spectral behaviors of optical absorption and PL are consistent with a quantum confinement model throughout the sizes and shapes of the CdSe nanocrystals of the luminescent films. The effective bandgap energies determined from the PL peaks position are in good agreement with those estimated from the optical absorbance spectra.Investigations have shown that optical properties of CdSe/PAA nanostructure were influenced by the pores sizes of PAA. It was observed an increase in CdSe NCs size from 2.22 to 2.56nm when the average pores diameter of PAA increases from 30 to 180nm. This finding indicates an enhancement in PL intensity and a red-shift in PL emission peaks from 2.35 to 2.14eV. By applying the quantum confinement model, we demonstrated that the redshift of PL peak is attributed to the change of CdSe NCs size with the pores diameter and that their spectral behaviors are related to the shape and the size distribution of the nanoparticles.

Electrochemical fabrication of 2D and 3D nickel nanowires using porous anodic alumina templates

Mechanically stable nickel (Ni) nanowires array and nanowires network were synthesized by pulse electrochemical deposition using 2D and 3D porous anodic alumina (PAA) templates. The structures and morphologies of as-prepared films were characterized by X-ray diffraction and scanning electron microscopy, respectively. The grown Ni nanowire using 3D PAA revealed more strength and larger surface area than has grown Ni use 2D PAA template. The prepared nanowires have a face-centered cubic crystal structure with average grain size 15 nm, and the preferred orientation of the nucleation of the nanowires is (111). The diameter of the nanowires is about 50–70 nm with length 3 µm. The resulting 3D Ni nanowire lattice, which provides enhanced mechanical stability and an increased surface area, benefits energy storage and many other applications which utilize the large surface area.

(Invited) Growth of Ordered ZnO Nanorods Arrays Using Anodic Porous Alumina Templates

The fabrication of ordered semiconductor nanostructures has attracted increasing interest due to its applicability to various functional devices. Among them, the semiconductor nanorods array is one of typical nanostructures available for the functional optical devices including solar cells, and display devices due to its unique physical properties originated from the geometrical structures. Although various fabrication processes for the nanorod arrays have been reported, the efficient fabrication process of the ordered semiconductor nanorods array has not been established so far [1]. In the present report, the formation of the highly ordered semiconductor (ZnO) nanorods array based on anodic porous alumina templates will be presented. The anodic porous alumina, which is formed by anodization of Al in acidic electrolyte, is one of typical self-ordered material with highly ordered hole arrangement [2]. The advantage of this material is its high controllability of the geometrical structures based on the anodizing conditions. Especially, under the appropriate low voltage anodization condition, the highly ordered hole array structures with small hole interval and hole size can be obtained [3]. The hole interval and hole size in this highly ordered porous alumina were typically 25 nm and 10 nm, respectively. In the present work, ZnO nanorods arrays were fabricated through the hydrothermal reaction [4] using the anodic porous alumina as a template for the synthesis. Based on the present process, the highly ordered arrays of ZnO nanorods could be fabricated on the substrates. The geometrical structures of the ZnO nanorods arrays were controlled by changing the structures of the porous alumina templates. The obtained nanostructures will be applied to the fabrication of various kinds of energy conversion devices, which require the highly ordered nanostructures of semiconductors. 1. W. I. Park, D. H. Kim, S.-W. Jung, G.-C. Yi, Appl. Phys. Lett., 80, 4232 (2002). 2. H. Masuda and K. Fukuda, Science, 268, 1466 (1995). 3. H. Masuda, K. Takenaka, T. Ishii, K. Nishio, Jpn. J. Appl. Phys., 45, L1165 (2006). 4. T. Shinagawa, S. Watase, M. Izaki, Cryst. Growth Des., 11, 5533 (2011).

Morphological analysis and photoluminescence properties of hydrophilic porous anodic alumina formed in oxalic acid

Porous anodic alumina (PAA) templates were prepared via two-step anodization process in 0.3 M oxalic acid for different anodization durations (2–10 h with a step of 2 h). In this article, we report our studies on the morphological analysis and photoluminescence (PL) properties of hydrophilic PAA templates prepared at 8 and 18 °C. Two-dimensional fast Fourier transform was used to study the regularity ratio of PAA. It was found that for a longer anodization time (6, 8 and 10 h) the better array of pores observed with anodization potential of 40 V. The effect of anodization duration on the structural aspects including pore diameter, interpore distance, porosity and pore density were investigated in detail. It was observed that increase in anodization duration led to an increase in pore diameter and porosity. Contact angle measurement of PAA templates was carried out to confirm the hydrophilic nature. The relationship between morphology of PAA and PL emission bands was studied. The PL spectra of PAA templates show two emission sub-bands, which can be ascribed to two luminescence centers, F+ (band-1) and F (band-2), respectively.

Effects of Nanoporous Anodic Alumina Oxide on the Crystallization and Melting Behavior of Poly(vinylidene fluoride).

Poly(vinylidene fluoride) (PVDF) nanotubes were fabricated by melt-wetting into porous anodic aluminum oxide (AAO) templates with two different interfacial properties: one is pristine AAO, and the other is modified by FOTS (AAO-F). Their crystallization and melting behaviors are compared with those of a bulk sample. For the PVDF in AAO-F, the nonisothermal crystallization temperature is slightly lower than that of bulk, and the melting temperature is similar to that of bulk. For the PVDF in pristine AAO, when the pore diameter is 200 nm, the crystallization is induced by two kinds of nucleation: heterogeneous nucleation and interface-induced nucleation. On the contrary, in the AAO template with pore diameter smaller than 200 nm, only interface-induced nucleation occurs. The melting temperature of PVDF crystals in the pristine AAO is much higher than that of bulk which can be attributed to the presence of an interfacial layer of PVDF on the template inner surface. The interaction between PVDF and AAO template produces the interfacial layer. Such an interfacial layer plays an important role in enhancing the melting temperature of PVDF crystals. The higher melting peak is always observed when the PVDF is nonisothermally crystallized in the AAO template irrespective of the thermal erasing temperature suggesting the interfacial layer is very stable on the AAO template surface. If the PVDF nanostructures are released from AAO template, the higher melting peak disappears with the enhancement of thermal erasing temperature.