In addition to the powerful direct polymerization of monomers, the post-synthetic modification route, involving the reaction between the polymer reactive intermediate and small molecule, is another approach for the preparation of functional polymers, which might not be yielded from their corresponding monomers through the direct polymerization. This article reviews the recent progress of the utilization of the post functional strategy, for the preparation of new opto-electronic polymers, discusses the design and functionality of these polymers, and gives some outlooks for the further exploration in this field at the end of this paper. 2 exhibited interesting, even exciting in some cases, optical or electrical properties, with huge potential applications in the fields of light-emitting diodes (LEDs), solar cells, sensors, non-linear optics (NLO) and so on. 4-7 Generally, different functionalities could be realized by different functional blocks introduced to the polymer systems as side chains or in the main chains. As a result, functional groups were frequently implanted in the predesigned monomers, and then embedded into the yielded functional polymers, during the polymerization process. [8][9][10] However, this synthetic approach does not always work successfully, since the functional group may poison the catalysts to hamper the growth of the polymer chain, or the corresponding monomers are inherently instable or could not be stable under the polymerization conditions.Fortunately, an alternative strategy, the post functional strategy, makes up most of the pities of the traditional direct polymerization approach. 11-13 As a typical example in industry, polyvinyl alcohol (PVA) could only be yielded through the post functional approach (Chart 1), as its corresponding monomer, vinyl alcohol, is not stable. Similar cases existed in the preparation of many opto-electronic polymers, by utilizing various reactions including the frequently used ones of the azo coupling, esterfication, knoevengel condensation, Heck and "click" reactions. 14-17
Chart 1 The synthesis of PVA by post synthetic modificationIn comparison with the direct polymerization approach, as the post functional reactions take place on the polymers, the complete conversion from one reactive group to another is not so easy.However, the post functional strategy could tolerate many functional groups containing high polarity, or reactive moieties, or special kinds of atoms, achieving the missions inaccessible from the direct polymerization approach. In recent years, more and more functional polymers were obtained from the post functional strategy, vastly enriching the family of functional polymers 3 with new offered functionalities, including some special optical and electrical properties. Herein, in this paper, we would like to review the recent progress of optical and electrical polymers, which were obtained through the post functional strategy, and mainly focus on the modification of the linear polymers with post-synthesis in the side chains, and the detail...