## 3 Polymerization Reactions within AAO Templates
### Radical Polymerization  
The first attempts at conducting radical polymerizations in AAO nanoreactors were addressed at the synthesis of polymers inside or at the walls of the AAO nanocavities. Nevertheless, the mechanism and kinetics of polymerization process was not studied, neither the chemical nor the physical properties of the obtained polymers were looked at in detail. Figure 4: (**a**) Different magnifications of PANI into 45 nm AAO pores (**a**) and 300 nm AAO pore (**b**) and (**c**); (**b**) Raman spectrum of PANI bulk (**d**), PANI polymerized in AAO templates of 300 nm (**e**) and idem in 45 nm (**f**) [116]. Copyright 2016. Reproduced with permission from the publisher: Budapest University of Technology and Economics. Among the first examples of radical polymerization, [PERSON] et al., reported the polymerization of p-phenylene vinylene (PPV) inside alumina geometries of different dimensions (10-200 nm diameter) and in polycarbonate membrane filters [117]. PPV polymers were synthesized inside the nanopores or on the inner surface of templates by the chemical vapor deposition (CVD) polymerization of dichloro-p-xylene monomer and the subsequent thermal dehydrochlorination of the polymer, following the process described by [PERSON] et al. [118]. After thermal treatment under argon atmosphere, the PPV nanotubes and nanorods obtained were converted to the corresponding carbonized tubes and nanorods. The study of the obtained nanoobjects by SEM microscopy, IR, UV-Vis, Raman and photoluminescence spectroscopies revealed the formation of monodisperse nanotubes and nanorods. [PERSON] et al. [119] proposed a nondestructive method to replicate the AAO templates by minimizing the adhesion between the nanofibers formed inside the nanopores and the pore walls. First, authors coated the AAO walls with 1H, 1H, 2H, 2H perfluorodecyltrichlorosilane in order to obtain a 40 nm-thick multilayer of the polymerized silane coupling agent. Then photopolymerization reaction of an amine-modified oligoetheracrylate resin was carried out by UV light in the AAO hard templates at room temperature with the aid of a free radical photoinitiator. In order to extract the arrays of synthesized polyacrylate nanofibers from the AAO hard templates, a nondestructive mechanical method was applied. As an example of the surface grafting of functional polymers on AAO template walls, [PERSON] and coworkers [120] studied the surface grafting of thin films of Poly(\(\gamma\)-benzyl-L-glutamate) PBLG within nanoporous anodic alumina (AAO) by surface-initiated polymerization of the N-carboxy anhydride of benzyl-L-glutamate (BLG-NCA) using 3-aminopropyltriethoxysilane (APTES) as a surface initiator. The authors claimed potential applications if a thin film of PBLG chains with multiple functional side chains is surface grafted, since it can offer a nanoporous platform with a very high density of functional sites. In a complementary work, [PERSON] et al. studied the pore diameter dependence of self-assembly and segmental dynamics of poly(\(\gamma\)-benzyl-L-glutamate) peptide nanorods confined in AAO [121; 122]. Recently, [PERSON] et al. [123] studied the thermal polymerization of the functional vinyl monomer based on diarylamino groups attached to a rigid and planar fluorene core (VB-FNPD) inside AAO channels with the aim of obtaining nanotubes that could be employed as nanocontainers for Fe\({}_{3}\)O\({}_{4}\) nanoparticles and thus make organic light-emitting polymer nanotubes. The functional VB-FNPD monomer, which contained diarylamino groups attached to a rigid and planar fluorene core to give the monomer efficient blue fluorescence, was polymerized thermally inside an AAO template. The new poly-VB-FNPD nanotubes were characterized showing their hollow nature and intense blue fluorescence. In addition, the nanotubes exhibited mechanical flexibility and semi-conductivity.