## 3 Results and Discussion
### The Influence of Functional Comonomers on the Pore Structure of POPs  
The influence of functional comonomers on the formation of a nanoporous structure was investigated firstly. As shown in Figure 2, quite different N\({}_{2}\) sorption isotherms (Samples 1, 3, 4, 5, and 6 with St, HEMA, HPMA, GMA, VBC as functional comonomers, respectively, and Sample 2: DVB only) mean that quite different porous structure were produced by dispersion polymerization in ethanol/deionized water (V:V = 9:1) from these different functional comonomers. The PDVB-based POPs prepared with functional comonomers such as HEMA and HPMA are highly porous, and the PDVB without other functional comonomers is moderately porous, while the POPs synthesized with GMA, VBC, and St (actually with no other functional group and non-cross-linking ability compared with DVB) are poorly porous. Therefore, the type of the chosen functional comonomer in the synthesis is an important factor of tuning the pore structure of prepared POPs. From the nitrogen sorption isotherms of these functional POPs, we can also reasonably infer that two major factors of the used comonomers could influence the porous structure of the prepared POPs. The first one is the functional group on the selected comonomer; the polarity of the prepared POPs were changed when changing the functional comonomer, which would vary the thermal compatibility between the prepared POPs with the solvent system, and the porous structure could be adjusted by the thermodynamic compatibility. Generally, a highly porous structure was produced from a thermodynamic compatible system, and a nonporous structure was generated from systems with bad thermodynamic compatibility, which could be explained by the classical pore-formation mechanism of porous polymer microspheres. The second factor is the cross-linking content in the prepared functional POPs; when a kind of functional comonomer with only one polymerizable double bond is added, the cross-linking degree is actually decrease. Due to the amorphous nature of the prepared functional POPs, which make it impossible to characterize by X-ray crystallography, an NLDFT simulation was used to evaluate the pore size and pore-size distribution of these POPs. From Figure 3, we can see that the pore-size abundance of these POPs mainly focuses on a relatively wide range from 1 to 10 nm, except that GMA and styrene as comonomers resulted in nearly nonporous materials. HPMA and HEMA-functionalized PDVB are highly porous with well-defined cavities mainly scattering in micropores and narrow mesopores from 1.1 to 4.5 nm, and the cumulative SSA and PV of the HPMA- and HEMA-functionalized PDVB are about 250 m\({}^{2}\)/g and 0.264 cm\({}^{3}\)/g, and 240 m\({}^{2}\)/g and 0.256 cm\({}^{3}\)/g, respectively. The mode value (the  
Figure 2: N\({}_{2}\) sorption isotherms of porous organic polymers synthesized with different functional comonomers. highest peak) of pore diameter from the NLDFT analysis of the HPMA-functionalized PDVB is 1.3 nm in the range of micropores in the SSA and PV pore-size-distribution curves, and the mode values of pore diameter of HEMA-functionalized PDVB are 1.4 nm in the pore-size distribution of SSA and 2.2 nm in the pore-size distribution of PV in the range of micropores and narrow mesopores. Furthermore, we can see the larger pore size from above 4.5 nm contributes more to total pore volume than surface area. In contrast, the mode value of pore diameter of the VBC-functionalized PDVB is about 2.1 nm, which is similar to that of the PDVB, and the similar pore-size distribution could be explained by their approximate solubility parameters, and the decrease of abundance of pore-size distribution, despite similar pore-size distribution, could be explained by the worse thermal compatibility of VBC with the mixture solvent and the decrease of cross-linking degree by adding the non-cross-linking functional comonomer VBC.