## 5 Future Perspectives and Challenges  
There is now an increasing tendency towards integrating technology and coherent classical routes to achieve high-\(k\) polymer nanocomposite materials. With this conditioned stimulus, the enhancement of the dielectric responses of high-\(k\) polymer nanocomposites with physiochemical and electromechanical stability is always a challenging motif. Since the stoichiometric aspect ratio and surface properties of nanoparticles to dielectric matrix also decides the ultimate properties for specialized applications, the development of functional organic moieties to alter the inorganic nano-architectures will need to be customized to acquire optimized high-\(k\) nanoparticles. A great deal of synthetic knowledge is also necessary, and this can bring more reliable high-\(k\) materials for organic electronics applications. Recent  
\begin{table} \begin{tabular}{c c c c c} \hline \hline
**Nano-Fillers** & **Dielectric Matrix** & \
\begin{tabular}{c} **Weight \% of** \\ **Nano-Fillers** \\ \end{tabular} &
\begin{tabular}{c} **Dielectric** \\ **Constant** \\ \end{tabular} & **References** \\ \hline Iron oxide (Fe\({}_{3}\)O\({}_{4}\)) & Polydimethylsiloxane & 60.0 & 9.0 & [140] \\ Copper/copper oxide & Polypropylene & 3.0 & 9.0 & [141] \\ Cu/CuO & & & & \\ \({}^{\mathrm{a}}\) Silicon dioxide & DGE-BA \({}^{\dagger}\) & 3.0 & 11.4 & [142] \\ Aluminum oxide (Al\({}_{2}\)O\({}_{3}\)) & Polyvinyl alcohol & 70.0 & 12.0 & [143] \\ \({}^{\mathrm{b}}\) Ba\({}_{0.2}\)Sr\({}_{0.3}\)TiO\({}_{3}\) & Polyvinylidene fluoride & 7.5 & 18.0 & [144] \\ Silver and Nickel (Ag/Ni) & Polydimethylsiloxane & 30.0 & 35.0 \({}^{\mathrm{c}}\) & [145] \\ \({}^{\mathrm{d}}\) BaTiO\({}_{3}\) & Polyvinylidene fluoride & 50.0 & 80.4 & [146] \\ BaTiO\({}_{3}\) & P(VDF-TrFE-CFE) \({}^{\dagger}\) & 50.0 & 108.0 & [147] \\ MWCNT/AgNP & Polyvinyl alcohol & 1.0 & 620.0 \({}^{\mathrm{e}}\) & [148] \\ Ni/BaTiO\({}_{3}\) & Polyvinylidene fluoride & 0.22 \({}^{\mathrm{f}}\) & 800.0 & [149] \\ MWCNT & Polyvinyl chloride & 4.0 & 13066.0 & [138] \\ \hline \hline \end{tabular}  \({}^{\mathrm{a}}\) nanoparticle size = 20 nm, \({}^{\mathrm{b}}\) nanowires, \({}^{\mathrm{c}}\) measured at 1 kHz, \({}^{\mathrm{d}}\) modified by polyvinyl pyrrolone (PVP), \({}^{\mathrm{e}}\) measured at 100 Hz, \({}^{\dagger}\) 0.22 volume fraction of Ni to BaTiO\({}_{3}\), \({}^{\mathrm{f}}\) (VDF-TrFE-CFE) = poly(vinylidene fluoride-trifluoroethylene) chloroform/bore  
advances in designing soft actuators and electro-mechano responsive 3D-printable artificial muscles need engineering expertise and skills, which facilitate the comprehensive dynamic structures. Due to their outstanding capability of recoverable deformation, dielectric elastomeric materials have been explored to design sensitive smart materials for external stimuli. Whilst the properties of the dielectric elastomers were less researched, by embedding functionalized high-\(k\) dielectric nanoparticles. The growing popularity of flexible electronics, also termed as flex circuits, is a technology to assemble electronic circuits on flexible/stretchable surface. This offers new solicitations in designing flexible and stretchable displays, flexible photovoltaic cell array panels, electronic circuits on fabrics, flexible wearable battery gadgets, etc. [159; 160; 161; 162]. The incorporation of high-\(k\) dielectric nanomaterials into a variety of flexible polymeric materials can be seen as exactly the right strategy in designing new functional materials. Considering the key issue of low dielectric constant behavior of polymer dielectric materials, an effective fabrication approach is also a prerequisite to improve the dielectric properties and it has been an essential research topic in the development of high-performance high-\(k\) polymer dielectric materials. Contributed to the writing, reviewing and editing of the final manuscript, [PERSON] and S.-Y.K. All authors have read and agreed to the published version of the manuscript.