# Metal-Coordinated Polymer-Inorganic Hybrids: Synthesis, Properties, and Application
## 3 Polymer-Inorganic Coordinated Hybrids: Complexation-Induced Properties
### Nano-Templated Hybrids
#### 3.3.2 Hybrid Induced Self-Assembled Nanomaterials  
In recent years, the integration of inorganic components into BCP systems has opened new pathways for designing hybrid nanomaterials. Incorporating inorganic components into BCPs not only expands the range of achievable properties but also influences the morphology of the resulting hybrid system. In a study by [PERSON] et al. [128], metal ions of Pb(II) and Fe(III) were incorporated into polystyrene-block-poly(4-vinylpyridine) (PS-b-P4 VP). This study employed 3D confinement in emulsion droplets, where the PS-b-P4 VP was confined within tiny droplets during solvent evaporation, leading to unique structural formations. The selective reaction of Pb(II) with 4 VP units resulted in shrinking the P4 VP domains through crosslinking interactions. As the concentration of Pb(II) ions increased, the morphology of the PS-b-P4 VP particles transitioned from lamellar (layered) to bent lamellar, eventually forming spherical domains. This morphological shift resulted from the change in geometric packing of the P4 VP domains due to Pb(II)-induced crosslinking, which altered the overall shape and internal structure of the assemblies (Figure 8c).  
Fe(III) ions, in contrast, introduced a different type of transformation. Initially, at low Fe (III) concentrations, the P4 VP chains formed a coordinated layer around the emulsion droplets, stabilizing an \"onion-like\" structure where the P4 VP domains concentrated near the droplet surface. However, at higher concentrations, Fe(III) ions hydrolyzed, lowering the pH and causing protonation of the P4 VP units. This protonation made P4 VP more hydrophilic, which decreased interfacial tension and caused instabilities in the emulsion droplets, leading to the breakup of the larger droplets into nanoscale vesicles and other smaller structures (Figure 8d).  
Figure 8: (**a**) (**i,ii**) SEM images of TiO\({}_{2}\) nanowires with a random alignment templated from self-assembled PS-b-PMMA BCP film on a QCM crystal after 8 SIS cycles at 135 \({}^{\circ}\)C [125]. (**b**) (**i,ii**) Top-view and cross-sectional SEM images of as-infiltrated self-assembled PS-b-P2 VP BCP thin films after Pt LPI for 75 s at 22 and 62 \({}^{\circ}\)C, respectively. (**iii,iv**) After oxygen-plasma ashing of the polymer matrix from the Pt-infiltrated PS-b-P2 VP BCP thin films in (**i,iii**). All scale bars denote 100 nm [34]. (**c**) TEM images and the corresponding schematic illustrations (upper-right insets) of the PS\({}_{9,8k}\)-b-P4 VP\({}_{10k}\)-Pb(II) particles obtained by solvent evaporation of emulsions containing PS\({}_{9,8k}\)-b-P4 VP\({}_{10k}\) in a chloroform phase (10 mg/mL) and Pb(II) ions with varied concentrations, (**i**) 0 M and (**ii**) 0.04 M, in PVA aqueous solution (3 mg/mL) [128]. (**d**) TEM images of the PS\({}_{9,8k}\)-b-P4 VP\({}_{10k}\)-Fe(III) assemblies obtained by solvent evaporation of emulsions containing PS\({}_{9,8k}\)-b-P4 VP\({}_{10k}\) in the chloroform phase (10 mg/mL) and Fe(III) with varied concentrations, (**i**) 0.001 M and (**ii**) 0.1 M, in PVA aqueous solution (3 mg/mL) [128]. Adapted with permission from the American Chemical Society [34; 125; 128].