NMRP versus “Click” Chemistry for the Synthesis of Semiconductor Polymers Carrying Pendant Perylene Bisimides

Abstract

The synthesis of well-defined polymers with pendant perylene bisimide (PBI) groups by a combination of nitroxide-mediated radical polymerization (NMRP) of trimethylsilyl propargyl acrylate followed by copper-catalyzed azide-alkyne cycloaddition (CuAAC, "click" chemistry) is described. The kinetics of NMRP of trimethylsilyl propargyl acrylate polymerization was monitored by 1 H NMR and size exclusion chromatography (SEC). Almost quantitative conversion in the "click" reaction with an azide functionalized PBI derivative was proven by FTIR and 1 H NMR analysis. Thus, semiconductor polymers carrying PBI pendant groups with M n up to 15800 g 3 mol -1 and polydispersity indices as good as 1.16 were obtained by this route. These polymers were compared with poly(perylene bisimide acrylate)s, PPerAcr-(CH 2 ) 11 , and PPerAcr(CH 2 ) 6 , which were synthesized by direct NMRP of PBI acrylates. These samples do not carry any triazol unit and they differ in their spacer length connecting the PBI unit to the main chain. All polymers were comparatively studied by SEC, thermogravimetry, differential scanning calorimetry, polarization microscopy, UV/vis spectroscopy, and photoluminescence measurements. The crystalline structure of the polymers was analyzed by X-ray diffraction. Inductively coupled plasma mass spectrometry analysis confirmed that copper content in the "click" polymer could be reduced down to 126 ppm (w/w).

Styrenated urethane oil synthesis via CuAAC “click” chemistry approach

“…Molecular weights of P(St-co-CMS)-cont, (PSt-N 3 )-cont and (PSt-OH)-cont are given in Table 3. According to the GPC results, polydispersity of the polymers remained below 1.5 in each step and this could indicate that controlled structure of the polymer chain has been protected as a result of the advantage of CuAAC "click" chemistry approach [32].…”

“…The resultant (PSt-TDI-PG)-cont3 sample gave good flexibility due to the proper distribution of hard and soft segments [8]. The optimum distribution of hard and soft segments [8] and optimum amount of urethane and 1,2,3-triazole [32] groups, which have important effects on the flexibility of the polymer films, could be achieved by using proper reactant ratios. The reaction between isocyanate and hydroxyl groups for the (PSt-TDI-PG)-cont3 preparation was monitored by FT-IR as shown in Fig.…”

“…It was mentioned that highly stable aromatic structure of 1,2,3-triazole part has an advantage of being resistant to acidic, basic and oxidative mediums [21][22][23]. Numerous applications of CuAAC introduce new routes in product design that have been recently studied for functionalization of polymers [22][23][24][25][26][27][28][29][30][31][32].…”

“…In another research, azide end-functional poly(oligo(ethylene glycol) acrylate) was synthesized and then it was used to prepare potential biocompatible polymers having functional end-groups such as -amino andhydroxy [24]. Likewise, NMRP and CuAAC combination having CuBr/PMDETA system was an efficient way to prepare semiconductors carrying pendant groups [32]. NMRP method ensures highly controlled structure and narrow molecular weight distribution for the final polymer in the presence of thermally stable free radical, 2,2 ,6,6 -tetramethylpiperidinyl-1-oxy (TEMPO) that provides dormant chains during the polymerization process by acting as a reversible terminating agent [8,9,32].…”

“…Likewise, NMRP and CuAAC combination having CuBr/PMDETA system was an efficient way to prepare semiconductors carrying pendant groups [32]. NMRP method ensures highly controlled structure and narrow molecular weight distribution for the final polymer in the presence of thermally stable free radical, 2,2 ,6,6 -tetramethylpiperidinyl-1-oxy (TEMPO) that provides dormant chains during the polymerization process by acting as a reversible terminating agent [8,9,32]. TEMPO is one of the hindered amine light stabilizers that protect coatings against photo-oxidative degradation [8].…”