## 4 Properties and Applications of Synthesized Polymers with AAO Templates
### Surface Properties: Wetting and Adhesion  
Superhydrophobicity is an important property for the development of self-cleaning, anti-corrosive or anti-fogging surfaces. This can be readily achieved by inducing multiple-scale roughness in a low surface energy material [161]. Polymer nanopillars and nanotubes, such as those resulting from templating AAO matrices, offer the ideal topography for the development of superhydrophobic surfaces as they mimic the ultimate level of roughness of some naturally occurring superhydrophobic surfaces, such as that of lotus leaves. This has triggered the study of wetting properties of these kinds of nanostructures in the last years. For example, [PERSON] et al. produced lotus-leaf-like surfaces with two different level of roughness by polymerizing styrene end-functionalized perfluoropolyether (PFPE) and a highly fluorinated styrene sulfonate ester (SS) within the nanopores of a pre-patterned AAO template. They conducted a thorough analysis of the wetting properties of these surfaces and demonstrated that they exhibited superhydrophobic characteristics, low contact angle hysteresis and self-cleaning features. In addition, they also performed theoretical calculations that suggested that these properties can be rationalized by assuming that water droplets are in the Cassie state on the nanopillar arrays. Nanostructured surfaces with two roughness levels were also produced by [PERSON] et al. employing an elegant approach [162]. First, they electrochemically polymerized PPY inside the nanopores. After the nanowires were released, Au nanoparticles were synthesized onto them by chemical methods. Finally, in order to decrease the surface energy of the material, the decorated nanowires were coated with heptadecafluoro-1-decanethiol. The system thus had two roughness levels that could be independently adjusted: a submicron-scale roughness resulting from the nanopillars and a nanoscale roughness from the Au nanoparticles. This allowed them to effectively tune the wettability of the surface. [PERSON] et al. electropolymerized polyaniline within nanoporous AAO films that were supported on Ti/Si substrates. After removal of the template, the polyaniline nanowires remained attached to the Ti/Si substrate, which enabled the fabrication of superhydrophobic and electrically conductive surfaces [163]. [PERSON] et al. presented the fabrication of acrylate-based surfaces with controlled wettability that included alternative superhydrophobic and hydrophilic regions [164]. Hydrophobic and hydrophilic regions were achieved by UV curing the resin employing a segmented master that contained pieces of AAO templates. [PERSON] et al. polymerized a intrinsically low surface energy fluorinated acrylic monomer (MFA) in AAO nanopores and measured a remarkable contact angle of 159\({}^{\circ}\) for the released nanostructured surface [125] (see Section 3.2 for further details). Nano- and microscale topography is known to be a key factor governing successful scaffold-cell interactions as cells are able to sense nano- and microscale features through specific responses [165; 166]. Thus, nanowires/nanotube arrays seem to be ideal platforms for investigating the interactions between cells and nano/microscale environments with the final goal of achieving topographical cellular control [167]. Recently, [PERSON] et al. prepared nanowires of \(\beta\)-Ketonitrile tautomeric copolymers using this approach, and after investigating their biocompatibility, cytotoxicity and degradation properties, they found that nanostructured scaffolds exhibited a higher degradation rate than non-nanostructured counterparts, with the value being compatible with typical bone regeneration times [168]. Furthermore, the \(\beta\)-Ketonitrile tautomeric copolymer nanowire arrays also permitted osteoblastic cell proliferation and differentiation without cytotoxic effects (Figure 14). [PERSON] et al.