Side-chain functionalized copolymers

SIDE-CHAIN FUNCTIONALIZED OR DENDRONIZED COPOLYMER HYBRIDS... 

Figure 5.5 Side chain functionalization of diblock copolymers 1 and 2, using a combination of hydrogen bonding and metal coordination.

Tew GN, Aamer KA, Shunmugam R. Incorporation of terpyridine into the side chain of copolymers to create multi-functional materials. Polymer 2005 46 8440-8447. 

With the aim of improving the photoinitiation activity of benzophenone/tertiary amine containing polymers, new polymeric systems having flexible spacers of different length inserted between the above side-chain functional groups and the backbone, have been proposed [22]. Indeed, copolymers of ABP, VBP... 

Due to the rather easy accessibility of novel functional polymer materials by click reactions, their potential scope of applications has significantly broadened in the last years. Through the preparation of functional thin polymer films, biohybrids, or self-assembly structures from end group or side chain functionalized polymers and functional block copolymers, applications, for example, as adhesives or additives, but especially also in optoelectronics, biomedicine, drug delivery, biochips, and micro- and nanoelectronics become accessible. 

Synthesis of PPE polymers and PPE copolymers relies on more traditional methods and so they have structural properties more in common with many other CP families. Study of PPEs homopolymers and, more recently, a subset of copolymers has been very much intensified over the last few years. Much of this interest has been motivated by the development of new facile synthesis routes, as discussed by Bunz [392], and specialized side chain functionalizations in reports by Zhou and Swager [393,394], designed... 

As pointed out already in Section 2.5.5, low-molecular weight ferroelectric liquid crystals (FLCs) and FLCPs are attracting a lot of interest because of their potential for electro-optical applications. The polymers offer new possibilities, e.g., as elastomers for piezoelectric elements or by copolymerization [77, 78, 105] due to the formation of intrinsic mixtures between SmC mesogenic units and other comonomers. This leads to FLCPs combining several material properties which might be utilized for colored displays in the case of comonomers containing chromophores. For the differentiated evaluation of such copolymers with reference to the possible exploitation of nonlinear optical (NLO) properties, the interplay of the different orientation tendencies of the side-chain functionalities is of crucial importance [36,106]. 

Figure 4.1 Schematic representation of dif- polymer, (c) Supramolecular block copolymer, ferent classes of supramolecular polymers. (d) Side-chain-functionalized supramolecular (a) Small-molecule main-chain supramolec- polymer, (e) Supramolecular network, ular polymer, (b) Branched supramolecular...

Rotello and coworkers [30] reported the first PNBE-based random copolymers with nucleobase-functionalized side chains, wherein longer linkers were utilized to achieve solubility. The system relied upon the complementary three-point H-bonding motif between uracil and diacyl DAP pendant groups on two respective polymer chains (figure 4.5a). The resulting side-chain-functionalized supramolecular polymers self-assemble into spherical polymersomes (figure 4.5b). 

Binder and Kluger [41, 42] utilized the Hamilton wedge and THY as molecular recognition handles in the construction of side-chain-functionalized poly(oxanorbornene dicarboximides) using a ROMP/click methodology. Monomers functionalized with azido or alkynyl side chains were polymerized to either homopolymers or block copolymers and subsequently subjected to Cu-catalyzed azide-alkyne cycloaddition [72] to install the desired H-bonding motifs. 

The copper-catalyzed azide/alkyne click reaction has found the broadest application in the modification of ROMP polymers, with the first reported example in 2004 by Binder and Kluger [13]. Since then, the copper-catalyzed click reaction has been used for the preparation of block copolymers [24, 29, 37], stars [18, 26], cycles [23], networks [25], and graft copolymers [27, 28, 38, 56, 57], as well as for end- [16] and side-chain-functionalized polymers [13, 17, 19-22, 48]. The most often used catalysts and bases for the azide/alkyne click reaction include copper(l) iodide, copper(l) bromide, trisftriphenylphosphine) copper(l) bromide, or copperfll) sulfate/sodium ascorbate as catalyst and diisopropylethylamine (DIPEA), pentamethyldiethylenetriamine (PMDETA), or 2,2 -bipyridine (bPy) as base. 

Moreover, dimethylsilane modified oxadiazole units were used to functionalize polystyrene-block-polyisoprene copolymers via Heck reaction or hydrosilation. The degree of side chain functionalization varied from 4-44% [98],... 

The ring-opening metathesis polymerization of side chain functionalized norbornene monomers was applied to obtain electroluminescent polymers (Scheme 38) [100,101]. Homo- and copolymers with 25 or 50 repeat units were prepared with ranging from 19,400-53,000Da and M jM = 1.02-1.04. The color of emission could be fine tuned by... 

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