## 5 Chemistry of Polymer Rods
### Chemical Structure of the Monomers and/or Post-Chemical Derivatization Reactions on the Product  
One important factor worth considering is the chemical structure of the monomers used, mainly in relation to the presence of the specific functional groups. The functional groups of the monomers could be used, in a further step of reaction, as anchored groups to immobilize specific ligands or to improve specific properties such as hydrophilicity, hydrophobicity, pH or temperature responsive stimuli. By choosing the correct functional monomer, monoliths for various applications can be designed. For example, two novel anion-exchange polymeric monoliths were prepared by direct copolymerization of 2-(diethylamino)ethyl methacrylate (DEAEM) and poly(ethylene glycol diacrylate) (PEGDA) or copolymerization of 2-(acryloyloxy)ethyl trimethylamonium chloride and PEGDA. The resulting monoliths contained diethyl aminoethyl (DEAE), a weak anion exchanger (WAX) group, and quaternary ammonium (QA), a strong anion exchanger (SAX) group, respectively. Both demonstrated comparable chromatographic properties and did not require additional surface functionalization. The dynamic binding capacities of the two monoliths were similar to or higher than values reported for other monoliths [58]. [PERSON] _et al._[59, 60, 61, 62] synthesized macroporous rods through ring-opening metathesis polymerization (ROMP) from bicyclic monomers within borosilicate columns and a ruthenium catalyst, and via the Schrock catalyst triggered ROMP [62]. [PERSON] _et al._ demonstrated that the performance of norbornene-based monolithic capillary columns prepared via ROMP was improved in separation capabilities for single and double-stranded nucleic acids as well as for proteins [59]. [PERSON] _et al._ reported ring-opening polymerization with synergistic comonomers [63] which contained in a boronate-functionalized polymeric monolith function as a single Wulff-type boronic acid ligand to enable the specific capture of _cis_-diol-containing biomolecules under neutral conditions. In other paper [64], [PERSON] _et al._ reported the preparation of a first-generation boronate functionalized polymeric monolithic column to be used for specific capture of _cis_-diol-containing compounds such as glycoproteins, RNA and carbohydrates. [PERSON] _et al._[65] developed affinity monoliths with a different immobilization strategy since the ligand (a peptide) was conjugated to one of the monomers of the polymerization mixture (GMA) prior to polymerization. Thus, after polymerization, a monolithic structure obtained was ready to use for affinity chromatography, for the purification of lysozyme (Lys). The use of GMA as co-monomer is frequent since it has excellent features due to the presence of epoxy groups which can rapidly react with various reagents. Therefore, the copolymer characteristics can be easily adjusted to the applications desired. Based on poly(GMA-co-DVB) monoliths, DEAE or QA functionalities were introduced to provide WAX or SAX stationary phases for the separation of oligonucleotides, or oligonucleotides and nucleosides, respectively [66; 67; 68]. [PERSON] _et al._[68] presented the preparation of a poly(GMA-co-EGDMA)-based monolith column for weak cation exchange chromatography and its use in the separation of biopolymers. Iminodiacetic acid (IDA)-type adsorbent was prepared by covalent coupling of IDA to the monolithic macroporous poly(GMA-co-EGDMA). Different metal ions (Cu\({}^{+2}\), Zn\({}^{+2}\), Ni\({}^{+2}\)) were immobilized on these columns and used for the separation of proteins [69]. Another monomer extensively used in the preparation of monoliths is CMS. Poly(CMS-co-DVB) was synthesized by [PERSON] _et al._ It was chemically modified and tested by separation of biopolymers. The chloro methyl groups of the monolith were used for chemical reaction with ethylenediamine (EDA) and then with chloroacetic acid. A weak cation exchange column was obtained after a two-step modification process [70].