Polymers with the same chemical composition can provide different properties by reducing the dimension or simply by altering their nanostructure. The recent literature reports hundreds of examples of advanced methods in the fabrication of polymer nanostructures accomplished following a variety of approaches, such as soft lithography, self-assembly routes, template assisted methods, etc. Polymer nanostructures with modulated morphologies and properties can be easily achieved from anodized aluminum oxide (AAO) template assisted methods. In the last decade, fabrication of polymer nanostructures in the nanocavities of AAOs has increased in interest since it allows the control and tailoring of the dimensions of a huge number of polymer and polymer-based composites materials. The fact that polymer dimensions may be adjusted allows the study of size-dependent properties. Moreover, using AAO template methods, modulated polymer nanostructures may be designed for specific applications. This review presents recent new insights in the fabrication methods of polymer nanostructures from hard porous AAO templates, with emphasis on the study of polymer structure/property relationships on the nanometric length scale, stressing potential interests in relevant applications. The discussion includes (i) a description of the anodizing methods and strategies to obtain AAO templates with adjusted dimensions; (ii) a summary of different infiltration methods, starting with the infiltration of a polymeric fluid (melt or solution) into the nanocavities of the AAO template, to conform a great number of the polymer nanostructures with different morphologies, the approach to obtain directly polymer nanostructures by in-situ polymerization of a monomer within AAO nanocavities and the effect of confinement in the AAO nanoreactor on the polymerization kinetics; (iii) an overview of the effects of confinement on structural aspects, dynamical processes and the mechanical, thermal and rheological properties of the polymer; (iv) examples of polymer nanostructures as precursors in bio-, adhesion, optical and electrical related applications; and finally (v) a summary of conclusions and suggested challenges.Acknowledgments Authors are gratefully acknowledged to the Ministerio de Economía y Competitividad for their financial support (MAT2011-24797 and MAT2014-53437). Rebeca Hernández thanks MEC for a Ramon y Cajal contract. Jaime Martína cknowledges support from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no. 654682Peer Reviewe

Polymer nanotechnology allows manipulating materials microstructure, morphology and compositional variation on the nanometer scale. Thus, it is able to provide materials for many cutting edge applications, from photonics to medical devices to sensors. This article summarizes recent work on template-based fabrication and on the basic properties of one-dimensional polymeric nanostructures and their inherent advantages over their conventional counterparts. The chemistry and physics relevant for the design of these nanostructured materials are discussed and recent advances emphasized. In particular, highlighting the effects of nanoconfinement on material behavior and putting somewhat greater emphasis on molecular motions. Some examples of one-dimensional-based polymeric nanostructures with promising applications for example in the field of tissue engineering are also presented as well as some aspects concerning recyclability of the used templates

Three-dimensional (3D) nanostructures combine properties of nanoscale materials with the advantages of being macro-sized pieces when the time comes to manipulate, measure their properties or make a device. However, the amount of compounds with the ability to self-organize in ordered 3D nanostructures is limited. Therefore, template-based fabrication strategies become the key approach towards 3D nanostructures. Here we report the simple fabrication of a template based on anodic aluminium oxide, having a well-defined, ordered, tunable, homogeneous 3D nanotubular network in the sub 100-nm range. The 3D templates are then employed to achieve 3D, ordered nanowire networks in Bi₂Te₃ and polystyrene. Finally, we demonstrate the photonic crystal behaviour of both the template and the polystyrene 3D nanostructure. Our approach may establish the foundations for future high-throughput, cheap, photonic materials and devices made of simple commodity plastics, metals and semiconductors.

Neutron spin echo has revealed the single chain dynamic structure factor of entangled polymer chains confined in cylindrical nanopores with chain dimensions either much larger or smaller than the lateral pore sizes. In both situations, a slowing down of the dynamics with respect to the bulk behavior is only observed at intermediate times. The results at long times provide a direct microscopic measurement of the entanglement distance under confinement. They constitute the first experimental microscopic evidence of the dilution of the total entanglement density in a polymer melt under strong confinement, a phenomenon that so far was hypothesized on the basis of various macroscopic observations.

Organic solar cells are thought to suffer from poor thermal stability of the active layer nanostructure, a common belief that is based on the extensive work that has been carried out on fullerene-based systems. We show that a widely studied non-fullerene acceptor, the indacenodithienothiophene-based acceptor ITIC, crystallizes in a profoundly different way as compared to fullerenes. Although fullerenes are frozen below the glass-transition temperature T_g of the photovoltaic blend, ITIC can undergo a glass-crystal transition considerably below its high T_g of ∼180 °C. Nanoscopic crystallites of a low-temperature polymorph are able to form through a diffusion-limited crystallization process. The resulting fine-grained nanostructure does not evolve further with time and hence is characterized by a high degree of thermal stability. Instead, above T_g, the low temperature polymorph melts, and micrometer-sized crystals of a high-temperature polymorph develop, enabled by more rapid diffusion and hence long-range mass transport. This leads to the same detrimental decrease in photovoltaic performance that is known to occur also in the case of fullerene-based blends. Besides explaining the superior thermal stability of non-fullerene blends at relatively high temperatures, our work introduces a new rationale for the design of bulk heterojunctions that is not based on the selection of high-T_g materials per se but diffusion-limited crystallization. The planar structure of ITIC and potentially other non-fullerene acceptors readily facilitates the desired glass-crystal transition, which constitutes a significant advantage over fullerenes, and may pave the way for truly stable organic solar cells.