## 3 Results and Discussion
Figure 2: Nanoindentation experiments showing the Young’s Modulus (GPa) as a function of the indentation depth HCPEG, porous HCPEG, and porous HCPEG filled with PANI (0.8% wt) (c) and PANI (0.8% in wt) plus GNNs (0.4% wt). As proof of concept of phase-specific loading, we first loaded the oil phase with polyaniline emeraldine salt doped by camphysulfonic acid (PANI), and the pores with gold nanowires networks (GNWs). Polyaniline emeraldine salt is a semiconductive polymer featuring many advantages over other semiconducting polymers such as low cost, easy synthesis, range of electrical conductivities, and unique reversible proton doping/de-doping processes [48]. The semi-conductiv emeraldine salt form of polyaniline features a partially filled valence band, which makes it electrically semiconductive via hopping of delocalized radical polaron. This condition makes this polymer highly polarizable and its polarizability depends on the valence band filling density. The polarizability of polyaniline determines its impedance response, and it can be tuned by modifying the radical polaron distribution through structural or chemical changes in the polymer chain. Despite its advantages, polyaniline is not easy to process because it is poorly dispersed in water and most organic solvents. Despite this, we found out that polyaniline doped CSA is easily dispersible in the low internal phase emulsion up to 0.8% wt. On the other hand, gold nanowires networks (GNWs) are 2D plasmonic nanostructures dispersed in water. These metallic nanostructures show catalytic activity, can be easily functionalized with biomolecules, and can serve as SERS substrates [45]. Furthermore, both fillers do not significantly affect the indentation profile (Figure 2). The thickness of the nanowires in the GNWs can vary from 4-5 nm to a few tens of nm and the extension of the network can reach several microns. The percentage of gold was 0.4% wt and it was the highest amount possible. Electron microscopy (TEM and SEM) of the composite materials gave insights into ultrastructure. Despite the loading of fillers in the phases composing the low internal phase emulsion, the composite materials retained the porous morphology (Figure 1e,g). Moreover, TEM and SEM analysis pointed out that each filler was included in specific regions, indeed GNWs were mostly included in the pores (Figure 1e), while polyaniline was dispersed in the HCPEG matrix (Figure 1g). Thus, phase selective loading of pores and polymer matrix could be achieved using this procedure. This selectivity is explained by considering that polyaniline is dispersible in PEG-DA but immiscible with water; instead, gold nanowires networks are dispersible in water and immiscible with PEG-DA. Moreover, during the preparation of the low internal phase emulsion, there is no contamination of the porosity with PANI although Au signals can be found both in the porosity and in the polymer matrix (Figure S1). Figure 1f shows a TEM image of GNWs which well compares to the GNWs included in the pores (Figure 1e). Statistical descriptors (Table 1) indicate that by increasing the loading of PANI in the porous HCPEG the porosity distribution shifts towards larger sizes and it becomes more dispersed. Figure 3: Confocal Fluorescence Microscopy of the internal of a non-porous HCPEG (**a**) and of a porous HCPEG matrix taken 5 min (**b**) and 30 min (**c**) after immersion in sulforhodamine B solution (1 mg/mL). The red color indicates the sulforhodamine B. Besides this, the effect of the GNWs filling on the pore size distribution was considered (Figure S2) and the higher was the concentration of GNWs the smaller and more uniform was the porosity. This effect recalls what is generally observed in Pickering emulsions [49] where nanostructures, due to their good wettability both in the oil and water phases, absorb on the droplets surface to form a coating to prevent them from gathering. In Figure 1e the nanostructures were localized at the edges of the pore, which once was the interface between oil and water phases.