Cationic Main‐Chain Polyelectrolytes with Pyridinium‐Based p‐Phenylenevinylene Units and Their Aggregation‐Induced Gelation

Abstract

Cationic polyelectrolytes find potential applications in electronic device fabrication, biosensing as well as in biological fields. Herein, a series of cationic main-chain polyelectrolytes with pyridinium-based p-phenylenevinylene units that are connected via alkylene spacers of varying lengths are synthesized by a base-catalyzed aldol-type coupling reaction. Their mean average molecular weights range from 15 000 to 32 000 g mol -1 , corresponding to about 16-33 repeat units. Due to the presence of alkyl side-chains and alkylene spacers as well as cationic hard-charges the polymers are endowed with amphiphilic character and hence, aggregation of these polyelectrolytes at high concentration leads to thermoreversible physical gel formation in dimethyl sulfoxide accompanied by interchain interactions. Morphological analysis shows spherical aggregates in case of C 16 -Poly-S 12 in dimethyl sulfoxide. Dependence of gelation behavior on the length of alkyl side-chains and alkylene spacers of the polyelectrolytes are addressed.for applications in sensing, [25][26][27][28][29] imaging, [30] as well as for enzyme activity, [31] and charge transport studies. [32,33] Fully conjugated poly(pyridinium salt)s, [34][35][36][37][38][39][40][41] or polyelectrolytes containing viologen, [42] as well as diethynylpyridinium units [43] as main-chain polyelectrolytes have been synthesized mainly for biosensing and optoelectronic applications. Nonconjugated polyelectrolytes were also generated based on ammonium, [44] pyridinium, [45][46][47][48][49] or viologen [50][51][52] as charged building blocks present either in the main or side chain. Also, nonconjugated polyelectrolytes containing main-chain perylene units have been reported. [53] Recently, polyelectrolyte-based dye-sensitized solar cells were fabricated from conjugated polymers with ammonium iodide side chains, [54] or based on imidazolium iodide-containing polymeric gel electrolytes [55,56] as well as 1-methyl-3-hexyl-imidazolium iodide blended in low molecular mass organogelators. [57] Nonconjugated λ-shaped polymers containing carbazole units that are connected via 4-pyridinium vinyl linkages have been synthesized showing interesting nonlinear optical properties. [58] Recently, pyridiniumbased p-phenylenevinylene trimers were synthesized [+]

Poly(Pyridinium Salt)s Containing 2,7-Diamino-9,9′-Dioctylfluorene Moieties with Various Organic Counterions Exhibiting Both Lyotropic Liquid-Crystalline and Light-Emitting Properties

“…The formation of aggregates other π-conjugated polyelectrolytes in water is widespread in the literature. It is likely that the extensive π-π interactions of the backbone and electrostatic interactions of ionic groups in the side chain with the solvents, among other factors, are responsible for the aggregates [ 55 , 87 , 88 ]. This mechanism is also supported by the theoretical molecular dynamics simulations of the aggregation of 9,9′-bis(4-phenoxy-butylsulfonate) fluorene-2,7-diyl and 1,4-phenylene tetramer in water [ 89 ].…”

Main-Chain Cationic Polyelectrolytes: Design, Synthesis, and Applications

“…Apart from the creation of the charge in the quaternary ammonium unit during the course of the polymerization, charges can be generated at either an earlier or later stage. A dipicolinium derivative connected with a spacer can undergo aldol-type coupling to produce cationic polyelectrolytes, where the charges were incorporated before polymerization . Alternatively, a tertiary amine-containing polymer can be synthesized first, and then it can be quaternized in the post-polymerization step to obtain the main-chain cationic polyelectrolytes .…”

“…Chemical structure and thermoreversible sol–gel transformation of the polyelectrolyte C 16 -Poly-S 12 in DMSO and the corresponding STEM image of the DMSO gel. This figure was reproduced with permission from ref . Copyright 2017 John Wiley and Sons.…”

Designing Imidazolium Poly(amide-amide) and Poly(amide-imide) Ionenes and Their Interactions with Mono- and Tris(imidazolium) Ionic Liquids

“…There have been abundant research efforts in recent decades dedicated to the design and applications surrounding polyelectrolytes and ionomers which contain charged features pendant to the main chain, highlighted in several reviews [1][2][3][4][5][6]. The design of ionic liquids (ILs) undoubtably serves as an influential synthetic inspiration for polyelectrolytes, which possess essentially The utility of ionenes has been demonstrated in separations and CO2 capture [8][9][10][11][12][13], ionexchange or conducting membranes [14], antimicrobial coatings [15][16][17][18], batteries [19][20][21], electrochromic devices [22], hydrogels and gelators [23][24][25], water treatment [26], and fiber applications [12,27,28]. Nearly all known ionenes bear cationic moieties such as ammonium, phosphonium, pyrrolidinium, pyridinium, triazolium, and imidazolium groups [8,14,20,22,23,[29][30][31][32][33][34].…”

“…The utility of ionenes has been demonstrated in separations and CO 2 capture [ 8 , 9 , 10 , 11 , 12 , 13 ], ion-exchange or conducting membranes [ 14 ], antimicrobial coatings [ 15 , 16 , 17 , 18 ], batteries [ 19 , 20 , 21 ], electrochromic devices [ 22 ], hydrogels and gelators [ 23 , 24 , 25 ], water treatment [ 26 ], and fiber applications [ 12 , 27 , 28 ]. Nearly all known ionenes bear cationic moieties such as ammonium, phosphonium, pyrrolidinium, pyridinium, triazolium, and imidazolium groups [ 8 , 14 , 20 , 22 , 23 , 29 , 30 , 31 , 32 , 33 , 34 ]. While variation of cationic and anionic groups in polyelectrolytes have been studied, there is limited work probing the specific effects of cation and anion variation in ionenes [ 35 , 36 , 37 ].…”