## 3 Results and Discussion
### St-Co-DVB Polymerization in the Presence of Surface-Modified SNps
#### 3.3.2 Hybrid St-DVB Monolith Preparation Using VBS Surface-Modified SNPs  
At 2 and 3 wt% DVB, the polymerizations led to the formation of monoliths with bicontinuous morphologies, and thus, it can be concluded that copolymer-SNP clusters are not formed at the polymerizations' early stage. As the DVB concentration is higher, in these experiments, the flexibility, size, and number of tethered chains should differ from the tethered chain properties of amphiphilic SNPs, formed at 1 wt% DVB. In view of the crosslinking increase, the chain entanglement between tethered SNPs is reduced and weaker hydrophobic interactions between amphiphilic particles are induced. At a high crosslinking concentration, it is expected that the polymer tethered chains, attached onto the SNPs, are reduced in size and flexibility [66]. Thus, the amphiphilic SNPs preferably adsorb at the monomer-water droplets' interface, due to a pronounced amphiphilic character provided by the presence of hard hydrophobic patches on their surface. Therefore, during the ongoing polymerization, hydrophobic patchy SNPs progressively anchor at the monomer droplets' interface, where they continue polymerizing, in the presence of hydrophilic surface-modified SNPs anchored therein, from the beginning of the preemulsion preparation [37]. Consequently, the droplets' interface is characterized by the presence of SNPs with rising hydrophobicity, by virtue of their ongoing polymerization and hydrophilic SNPs, which will further polymerize. Therefore, the droplets' interface is progressively subjected to a competition between hydrophobic and hydrophilic patchy nanoparticles, both exhibiting an increase in the average molecular weight of the hydrophobic patches caused by polymerization. As a result of the high density of patchy SNPs with increasing hydrophobicity at the droplet interface, the radius of curvature of the amphiphilic particles varies continuously until yielding to an emulsion inversion, or separation, because of wettability changes. However, caused by the presence of both hydrophilic and hydrophobic SNPs at the oil-water interface, the emulsion destabilization process does not totally succeed, and bijels are formed at this stage of the Pickering emulsion polymerization [37]. Indeed, bijels, or bi-continuous emulsions, are defined as inter-penetrated structures of two immiscible liquids that share a layer of hydrophobic and hydrophilic colloidal nanoparticles at the interface [67; 68; 69]. These bijels are defined as jammed emulsion gels that can be prepared via homogenization [70], but their stabilization requires the use of both hydrophilic and hydrophobic nanoparticles, which wet the aqueous and oil phases equally. Shortly after, it is likely that the patchy SNPs' adsorption, at the droplet interface, results in the formation of jammed gel emulsions due to the presence of hydrophobic and hydrophilic SNPs tethered particles, characterized by polymer chains of different average molecular weight, which allow wetting the water and monomer phases equally [70]. Finally, the ongoing polymerization in the bijels will continue until complete conversion of monomers to generate percolated monoliths with bi-continuous porosity. For better clarity, the polymerization mechanisms that occurred in Pickering emulsions with an acid-continuous-aqueous phase are schematically described in Figure 6.  
Briefly, at pH = 5, DVB as a crosslink interferes specifically in the nucleation step of the reaction by modifying the length and flexibility of the tethered oligomer chains. By adding different DVB contents in the initial Pickering emulsion charge, it is possible to tune the amphiphilicity of the patchy SNPs, which results in the formation of bijels, representing a key step in the formation of percolated monoliths. Thus, this study reveals a new perspective in the use of crosslinking agents to prepare and design new hybrid percolated monoliths with extraordinary properties.