# Novel Polymer Sorbents with Imprinted Task-Specific Ionic Liquids for Metal Removal
## 3 Results and Discussion
### Structural and Thermal Characterization of the Sorbents
The shape of the grains is perfectly spherical, and there is an occasional defect that looks similar to a dent from an adjacent ball. Since there is a small population of spheres connected, those with a slight deformation of the shape may be the effect of separation of previously connected balls. The surface of the grains is smooth, and it contains a small number of pores in the form of round holes with a diameter of up to about 1 micrometer. There is also a small population (less than 10%) of very small spheres: 25-75 micrometers. In the case of VBBr, it was indicated that the condition of the substitution reaction caused partial damage to the VBC spheres. Approximately 50% of the beads have been fragmented into several pieces large enough to see areas that were previously the surface of the ball on them. There was no complete decomposition, only cracking. Sizes similar to the undissolved VBC with a mean diameter of 133 micrometers with a mean variation of 31 micrometers and a diameter spread of 90-250 micrometers. The size and shape of the crumbs indicate that the balls break into several or a dozen parts. The pores inside the broken balls are of a spherical shape, constituting a small part of the volume of the spheres. These voids have a diameter of 1 to 5 micrometers. The fractures themselves contain sharp edges, typical for brittle fracture. The surface of undamaged spheres has no holes visible on the VBC. The analysis of the VBC and VBBr  
Figure 2: Raman spectra of VBBr (**a**) and VBC (**b**) before and after modification with Ox3.10 and Ox4.10, Raman map of VBC-Ox3.10 (**c**) and Raman spectra with marked bands on the basis of which the map was obtained (**d**). after functionalization with the pyridine derivatives did not reveal any further changes in the morphology and shape of the particles. The measurement of the contact angle provides information on the wettability of water on the sorbent surface. The results obtained show a close correlation between the structure of functional groups and the hydrophilicity of the sorbents (Table S1). The presence of bromide counter ions on the polymer surface causes poor surface wetting (\(\theta>90^{\circ}\)). On the other hand, the surface of the VBC series sorbents shows a contact angle much below \(90^{\circ}\), which allows us to classify these materials as hydrophilic. Moreover, substitution on the 4-position of the pyridine ring yields higher contact angle values than that observed for 3-analogue, and the ketones are less hydrophilic than the corresponding oximes. The thermal stability of the synthetized materials was examined by thermogravimetric analysis (TGA). Figure 4 shows the TGA curves of two types of copolymers VBC and VBBr, and products of their modification with the appropriate pyridine derivative. Figure 4 shows the weight loss of the materials when heated up to 600 \({}^{\circ}\)C under nitrogen atmosphere. As can be seen, copolymers present three steps of decomposition. The first one, occurring at a temperature below 100 \({}^{\circ}\)C, can be attributed to the evaporation of the residual solvents used during the synthesis and purification of the sorbents, which are absorbed in samples. The next two are weight losses of copolymer. At a lower temperature range, the decomposition of pendant groups and then decomposition of the crosslinked network of copolymer occur. The initial decomposition temperatures were taken as onset of the weight loss and presented in Table 2. The thermal stability of both copolymers is in the temperature above 300 \({}^{\circ}\)C, and the copolymer VBC has greater thermal stability (T\({}_{\rm onset}\) = 382 \({}^{\circ}\)C) than the copolymer with VBBr by approximately 50 \({}^{\circ}\)C (T\({}_{\rm onset}\) = 336 \({}^{\circ}\)C). Modification of the copolymers structure causes a decrease in the thermal stability of the starting polymers and the appearance of additional degrees of decomposition on the curves related to the grafted structures.