Controlling supramolecular polymerization through multicomponent self‐assembly

The self‐assembly into supramolecular polymers is a process driven by reversible non‐covalent interactions between monomers, and gives access to materials applications incorporating mechanical, biological, optical or electronic functionalities. Compared to the achievements in precision polymer synthesis via living and controlled covalent polymerization processes, supramolecular chemists have only just learned how to developed strategies that allow similar control over polymer length, (co)monomer sequence and morphology (random, alternating or blocked ordering). This highlight article discusses the unique opportunities that arise when coassembling multicomponent supramolecular polymers, and focusses on four strategies in order to control the polymer architecture, size, stability and its stimuli‐responsive properties: (1) end‐capping of supramolecular polymers, (2) biomimetic templated polymerization, (3) controlled selectivity and reactivity in supramolecular copolymerization, and (4) living supramolecular polymerization. In contrast to the traditional focus on equilibrium systems, our emphasis is also on the manipulation of self‐assembly kinetics of synthetic supramolecular systems. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 34–78     

Direct arylation polymerization toward a narrow bandgap donor–acceptor conjugated polymer of alternating 5,6‐difluoro‐2,1,3‐benzothiadiazole and alkyl‐quarternarythiophene: From synthesis,optoelectronic properties to devices

ABSTRACT: Direct arylation polymerization (DAP) enabled facile synthesis of a narrow bandgap donor–acceptor conjugated polymer (PDFBT‐Th₄) composed of alternating 5,6‐difluoro‐2,1,3‐benzothiadiazole and alkyl‐quaternarythiophene. The optimized reaction condition of DAP catalyzed with Pd(OAc)₂/(o‐MeOPh)₃P/PivOH/K₂CO₃ in o‐xylene led to the target polymer with a number‐average molecular weight (M_n) of 14.6 kDa without noticeable homocoupling or β‐branching defects. UV‐vis absorption spectra of PDFBT‐Th₄ indicate strong interchain aggregation in films. While the C‐H selectivity and the alternating polymer structure of PDFBT‐Th₄ synthesized via DAP are comparable to those of the same type polymers synthesized via Stille coupling, the batch of PDFBT‐Th₄ synthesized via optimal DAP, despite its lower M_n, showed higher hole mobility in field effect transistors and larger power conversion efficiency in organic solar cell devices. These results further demonstrate the promising potential of DAP for efficient synthesis of high‐performance D‐A conjugated polymers for broad optoelectronic applications. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1869–1879     

Radical polymerization of novel N‐substituted‐N‐vinylformamide derivatives with bulky chiral substitutents

A series of novel N‐substituted‐N‐vinylformamides were synthesized, and the effect of bulky substituents on their radical polymerizability and polymer structure were investigated. N‐(p‐Methoxybenzyl)‐N‐vinylformamide ( 3 ) and N‐cyclohexylmethyl‐N‐vinylformamide ( 4 ) generated polymers, while it was known that their N‐vinylacetamide derivatives did not. ¹H NMR and ¹³C NMR analyses of poly( 3 ), however, revealed almost no difference among the various polymerization conditions, implying that the substituent bulkiness did not influence the polymer structures. On the other hand, the chiral polymers, which were obtained by the radical polymerization of N‐(S)‐2‐methylbutyl‐N‐vinylformamide ((S)‐ 5 ) and N‐(S)‐2,3‐dihydroxypropyl‐N‐vinylformamide ((S)‐ 7 ) at 0 °C, showed sharper spectral patterns than those obtained at higher polymerization temperatures. Furthermore, the intensities of their positive cotton effects on circular dichroism increased when the polymerization temperature was low, suggesting that the substituent bulkiness of (S)‐ 5 and (S)‐ 7 influenced the polymer structures, such as their stereoregularity and regioregularity. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Hole‐transporting host‐polymer series consisting of triphenylamine basic structures for phosphorescent polymer light‐emitting diodes

A series of novel styrene derived monomers with triphenylamine‐based units, and their polymers have been synthesized and compared with the well‐known structure of polymer of N,N′‐bis(3‐methylphenyl)‐N,N′‐diphenylbenzidine with respect to their hole‐transporting behavior in phosphorescent polymer light‐emitting diodes (PLEDs). A vinyltriphenylamine structure was selected as a basic unit, functionalized at the para positions with the following side groups: diphenylamine, 3‐methylphenyl‐aniline, 1‐ and 2‐naphthylamine, carbazole, and phenothiazine. The polymers are used in PLEDs as host polymers for blend systems with the following device configuration: glass/indium–tin–oxide/PEDOT:PSS/polymer‐blend/CsF/Ca/Ag. In addition to the hole‐transporting host polymer, the polymer blend includes a phosphorescent dopant [Ir(Me‐ppy)₃] and an electron‐transporting molecule (2‐(4‐biphenyl)‐5‐(4‐tert‐butylphenyl)‐1,3,4‐oxadiazole). We demonstrate that two polymers are excellent hole‐transporting matrix materials for these blend systems because of their good overall electroluminescent performances and their comparatively high glass transition temperatures. For the carbazole‐substituted polymer (T_g = 246 °C), a luminous efficiency of 35 cd A^?1 and a brightness of 6700 cd m^?2 at 10 V is accessible. The phenothiazine‐functionalized polymer (T_g = 220 °C) shows nearly the same outstanding PLED behavior. Hence, both these polymers outperform the well‐known polymer of N,N′‐bis(3‐methylphenyl)‐N,N′‐diphenylbenzidine, showing only a luminous efficiency of 7.9 cd A^?1 and a brightness of 2500 cd m^?2 (10 V). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3417–3430, 2010     

Photoresponsive polymers and block copolymers by molecular recognition based on multiple hydrogen bonds

A new methacrylate containing a 2,6‐diacylaminopyridine (DAP) group was synthesized and polymerized via RAFT polymerization to prepare homopolymethacrylates (PDAP) and diblock copolymers combined with a poly(methyl methacrylate) block (PMMA‐b‐PDAP). These polymers can be easily complexed with azobenzene chromophores having thymine (tAZO) or carboxylic groups with a dendritic structure (dAZO), which can form either three or two hydrogen bonds with the DAP groups, respectively. The supramolecular polymers were characterized by spectroscopic techniques, optical microscopy, TGA, and DSC. The supramolecular polymers and block copolymers with dAZO exhibited mesomorphic properties meanwhile with tAZO are amorphous materials. The response of the supramolecular polymers to irradiation with linearly polarized light was also investigated founding that stable optical anisotropy can be photoinduced in all the materials although higher values of birefringence and dichroism were obtained in polymers containing the dendrimeric chromophore dAZO. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3173–3184     

Hyperbranched narrow‐bandgap DPP homopolymers synthesized via direct arylation polycondensation

Narrow bandgap and hyperbranched polymers (h‐PTDPP) are synthesized by directly arylation polymerization (DAP) of 2‐bromo‐thiophene‐flanked diketopyrrolopyrrole (Br‐TDPP) as the monomer. Their optical properties as well as chemical structures are studied. The detailed optimization of DAP conditions from catalyst, temperature, solvent, ligand to additive not only leads to high molecular weight h‐PTDPP, but also provides some insight to minimize structural defects in DAP when brominated TDPP is involved as a monomer. The increase in the degree of branching results in lower charge‐carrier mobilities in organic field‐effect transistors involving h‐PTDPP‐3 as the semiconducting channel. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1040–1047     

Norbornyl benzocyclobutene ladder polymers: Conformation and microporosity

Shape-persistent contorted ladder polymers are an intriguing and unusual class of polymers. Using catalytic arene-norbornene annulation (CANAL) polymerization and with norbornadiene and dibromoarenes as monomers, we synthesized a series of ladder polymers with fused norbornyl benzocyclobutene backbones and varied conformations. A diaryl spiro-orthocarbonate monomer was used to reorient the ladder backbone perpendicularly to induce three-dimensional kinks, and a p-dibromo-xylene comonomer was used to statistically vary the distance between the spirocyclic kinks in the ladder backbone. Norbornyl benzocyclobutene ladder polymers with no spirocyclic backbone twists possess much more compact conformations than ladder polymers with frequent spirocyclic backbone twists in solution. While spirocyclic twists in the polymer backbone had minor effects on the surface area and microporosity, incorporation of rotatable single bonds in the repeat unit significantly decreased both the surface area and pore volume. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3075–3081     

New polymers with mesogens in the side chain and kinked aromatic structures in the main chain from the polyaddition of bis(epoxide)s and di(ester)s

Nine polymers with kinked aromatic structures in the main chain and biphenylene‐type mesogenic groups in the side chain were synthesized by the polyaddition of bis(epoxide)s and thio‐ and O‐esters. Tetrabutylphosphonium chloride and tetraphenylphosphonium chloride effectively catalyzed the polymerization. The thermal behavior of the polymers was measured by DSC and polarizing optical microscopy. The effect of annealing time on the degree of crystallization was investigated by DSC analysis. Polymers containing 100% of the kinked aromatic groups and 1,3‐propylene glycol in the main chain were amorphous. However, when half of the main‐chain aromatic moieties were composed of kinked groups and the other half of the aromatics were linear rodlike groups, the polymers were crystalline. The incorporation of kinked groups into the main chain of side‐chain liquid‐crystalline polymers suppressed the formation of liquid crystallinity. The polymer with mesogenic aromatic structures in both the main chain and the side chain was capable of forming a liquid‐crystalline phase. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 988–998, 2000     

RAFT polymerization of a novel activated ester monomer and conversion to a terpyridine‐containing homopolymer

Developing new materials with unique properties for nanotechnology applications, in general, and supramolecular polymers, in particular, lie at the heart of much ongoing research. In line with these efforts, we have been exploring polymers containing terpyridine (terpy) in the side chain. Here we report a new monomer that effectively undergoes reversible addition fragmentation chain transfer polymerization (RAFT) to yield high‐molecular‐weight (M_n) polymers with narrow polydispersity (PDI). The monomer is an N‐succinimide activated ester of p‐vinyl benzoic acid. Under RAFT conditions, poly(N‐succinimide p‐vinylbenzoate)s were generated, with M_n ranging between 44 and 61 kDa and PDI of 1.03–1.07. One of these homopolymers was reacted with an amine functionalized terpy, creating a new homopolymer containing terpy ligands on every monomer. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5618–5625, 2007     

Hydrogen‐bonded supramolecular polymers from derivatives of α‐amino‐ε‐caprolactam: A bio‐based material

Hydrogen‐bonded supramolecular polymers were prepared from the derivatives of α‐amino‐ε‐caprolactam (ACL), obtained from a renewable resource. Several self‐complimentary bis‐ or tetra‐caprolactam monomers were synthesized by varying the number of carbons of the spacer between the hydrogen‐bonding end groups. Physical properties of these hydrogen‐bonded polymers were clearly demonstrated by differential scanning colorimetry, solid‐state NMR, and X‐ray powder diffraction analyses. The supramolecular behavior was also supported by fiber formation from the melt for several of these compounds, and stable glassy materials were prepared from the physical mixtures of two different biscaprolactams. The self‐association ability of ACL was also used by incorporating ACL at the chain ends of low‐molecular weight Jeffamine (M_n = 900 g/mol) using urea and amide linkages. The transformation of this liquid oligomer at room temperature into a self‐standing, transparent film clearly showed the improvement in mechanical properties obtained by the introduction of terminal hydrogen‐bonding groups. Finally, the use of monomers with a functionality of four gave rise to network formation either alone or combination with bifunctional monomers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Connectivity defects enhance chain dynamics in supramolecular polymer model‐network gels

Supramolecular polymer networks exhibit twofold dynamics: that of their polymer chains and that of the transient bonds between them, which is further complexed when irregular network structures lead to local variation of both. A typical irregularity is imperfect network‐chain connectivity. To assess the impact of that, we study the diffusion of three different types of tracer polymers in supramolecular model networks of four‐arm star‐shaped poly(ethylene glycol). First, we focus on tracers that carry three stickers and one fluorescent label at their four arms, thereby creating an inherent network connectivity defect in their vicinity. Second, we embed tracers that carry four stickers and four labels and that do not intrinsically create network defects. Third, we embed non‐sticky tracers with a larger size than the network meshes, thereby sterically obstructing their connectivity. These studies reveal that the first tracers can rapidly walk within the networks by sequential arm detachment above c*, whereas below c*, they are subject to a dynamic equilibrium of liberated and gel‐cluster‐bound portions. By contrast, the second tracers are efficiently incorporated into the network, which dramatically hinders their motion. Opposed to that, the third tracers can diffuse almost as unhindered as if they were embedded within an uncrosslinked matrix. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 19–29     

Optical and shape memory properties of semicrystalline poly(cyclooctene) upon cold‐drawing

Semicrystalline thermoplastic poly(cyclooctene) (PCO) shows significant improvement in transparency when cold‐drawn at room temperature, unlike other semicrystalline polymers whose fibrillated chains cause crazing upon cold‐drawing, making the polymers opaque to visible light. Upon heating, transparent cold‐drawn PCO recovers its original opacity as well as its undeformed shape. In situ wide‐ and small‐angle X‐ray diffraction and polarized Fourier transform infrared analyses show that molecular density differences between the PCO crystalline and amorphous phases were reduced due to strain‐induced crystallization and that fibrillated chains and voids, an indication of craze, were not observed due to chain entanglements concentrated in trans double‐bond regions. These two factors explain the unique optical properties of PCO. Finally, it is demonstrated that crosslinked PCO enhanced optical and shape memory recovery without deterioration of the transparency of the polymer. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 1595–1607     

Melamine driven supramolecular self‐assembly of nucleobase derivatives in water

Water‐soluble supramolecular polymers, especially made up of biomolecules, are ideally suited to build new biomaterials that can mimic or interact with dynamic, biological environments. Here, two derivatives from thymine (T), that is N‐[2‐(3,4‐Dihydro‐5‐methyl‐2,4‐dioxo‐1(2H)‐pyrimidinyl)acetyl]‐L‐phenylalanine (T‐phe) and N‐(2‐Aminoethyl)‐3,4‐dihydro‐5‐methyl‐2,4‐dioxo‐1(2H)‐pyrimidineacetamide (T‐NH₂) were synthesized. Then the optimal condition for self‐assembly of T‐phe and T‐NH₂ driven by melamine (M) was explored. It was observed that M/T kept at 1:3 with equivalent T‐phe and T‐NH₂ under neutral environment resulted in long fibers (>1 μm) with extremely high aspect ratios, which suggested that electrostatic and π‐stacking interactions could be effectively orchestrated by hydrogen bonds to direct the hierarchical assembly. Furthermore, hydrogels were spontaneously generated with a concentrated solution of T‐phe, T‐NH₂, and M due to the fibril entanglement. Given its biomimetic nature and efficient self‐assembly process, this newly developed supramolecular polymer stacked by tetrameric structures represented an innovative concept and pathway for novel bio‐inspired materials. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 789–796     

Fast and effective copper(0)‐mediated simultaneous chain‐ and step‐growth radical polymerization at ambient temperature

Vinyl‐conjugated monomer (methyl acrylate, MA) and allyl 2‐bromopropanoate (ABP)‐possessing unconjugated C?C and active C? Br bonds were polymerized via the Cu(0)‐mediated simultaneous chain‐ and step‐growth radical polymerization at ambient temperature using Cu(0) as catalyst, N,N,N′,N″,N″‐pentamethyldiethylenetriamine as ligand and dimethyl sulfoxide as solvent. The conversion was reached higher than 98% within 20 h. The obtained polymers showed block structure consisting of polyester and vinyl polymer moieties. The Cu(0)‐catalyzed simultaneous chain‐ and step‐growth radical polymerization mechanism was demonstrated by NMR, matrix‐assisted laser desorption ionization time‐of‐flight, and GPC analyses. Furthermore, the obtained copolymers of MA and ABP were further modified with poly(N‐isopropylamide) through radical thiol‐ene “click” chemistry from the terminal double bond. The thermoresponsive behavior of this block copolymer was investigated. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 3907–3916     

Reactive ligand influence on initiation in phenylene catalyst‐transfer polymerization

Synthesizing conjugated polymers via catalyst‐transfer polymerization (CTP) has led to unprecedented control over polymer sequence and molecular weight. Yet many challenges remain, including broadening the monomer scope and narrowing the molecular weight dispersities. Broad polymer dispersities can arise from nonliving pathways as well as slow initiation. Previously, slow initiation was observed in Ni‐mediated CTP of phenylene monomers. Although precatalysts with faster initiation rates have been reported, the rates still do not exceed propagation. Herein a second‐ and third‐generation of reactive ligands are described, along with a simple method for measuring initiation rates. A precatalyst with an initiation rate that exceeds propagation is now reported, however, the resulting polymer samples still exhibit broad dispersities, suggesting that slow initiation is not the most significant contributing factor in Ni‐mediated phenylene polymerizations. In addition, initiation rates measured under authentic polymerization conditions revealed that both exogenous triphenylphosphine and an ortho‐trifluoroethoxy substituent on the reactive ligand have a strong influence. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1530–1535     

Novel hyperbranched polymers synthesized via A3 + B(B′) approach by radical addition‐coupling polymerization

In this study, a novel application of radical addition‐coupling polymerization (RACP) for synthesis of hyperbranched polymers is reported. By Cu/PMDETA‐mediated RACP of 2‐methyl‐2‐nitrosopropane with trimethylolpropane tris(2‐bromopropionate) or a bromo‐ended 3‐arm PS macromonomer, two types of hyperbranched polymers with high degree of polymerization are synthesized under mild conditions, respectively. The chemical structures of the hyperbranched polymers are carefully characterized. By selective degradations of the ester groups and weak bonds of NO? C in the polymers, high degree of alternative connection of the two monomers in the synthesized polymers have been identified. Based on the experimental results, mechanism of formation of the hyperbranched polymer is proposed, which includes formation of carbon radicals from the tribromo monomer through single electron transfer, its capture by 2‐methyl‐2‐nitrosopropane that results in nitroxide radical, and cross‐coupling reaction of the nitroxide radical with other carbon radicals. Hyperbranched polymer can be formed in a step‐growth mode after multiple steps of such reactions. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 904–913     

Small molecule self‐assembly in polymer matrices

Using small molecules in polymer matrices is common in applications such as (i) plasticizing polymers to modify the glass transition and mechanical properties and (ii) dispersion of photoactive or electroactive small molecules in polymer matrices in organic‐electronic devices Aggregation of these small molecules and phase separation leading to crystallization often cannot be morphologically controlled. If these are designed with self‐assembling codes such as hydrogen bonding or aromatic interactions, their phase separation behavior would be distinctly different. This review summarizes the studies on morphologies in such situations, such as (i) sub‐surface assembly in polymer matrices, (ii) controlled polymerization‐induced phase separation to create polymer blends, (iii) using the polymer to direct the assembly of small molecules in liquid crystalline devices, (iv) functionalizing a polymer with self‐assembling small molecules to cause organo‐gelation which the polymer itself would not by itself, and (v) using such systems as templates to create porous polymer structures. Organic–inorganic hybrids using polymers as templates for nanostructures and imprinted porous membranes is an emerging area. Since self‐assembly is one of the dominating area of research with respect to both small molecules, polymers as well as the combination of the two, this review summarizes the studies on the aforementioned topics. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 451–478     

Degradable alternating polyperoxides from poly(ethylene glycol)‐substituted styrenic monomers with water solubility and thermoresponsiveness

Water soluble alternating copolymers were prepared by oxidative free radical copolymerization of 4‐vinylbenzyl methoxypoly(oxyethylene) ether (PEGSt) and molecular oxygen at 50 °C. NMR spectroscopy established alternate sequence of PEGSt and peroxy bonds ( O O ) along the polymer main‐chain. The obtained polymers show temperature induced hydrophilic to hydrophobic phase separation, confirmed by UV‐visible spectroscopy and dynamic light scattering. The cloud point temperature (T_CP) of the polymers can be tuned by changing the chain length of side‐chain poly(ethylene oxide) and incorporation of hydrophobic methyl methacrylate in the copolyperoxides. Exothermic degradation of these polyperoxides was confirmed by differential scanning calorimetry and the degradation products have been characterized by electron impact mass spectroscopy. Finally, N,N‐dimethylacrylamide was polymerized in the presence of these polyperoxides in toluene, highlighting their potential as polymeric free radical initiator during polymerization of vinyl monomers. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2030–2038     

Synthesis and fluorescent properties of model compounds for conjugated polymer containing maleimide units at the main chain

2,3‐Diaryl substituted maleimides as model compounds of conjugated maleimide polymers [poly(RMI‐alt‐Ar) and poly(RMI‐co‐Ar)] were synthesized from 2,3‐dibromo‐N‐substituted maleimide (DBrRMI) [R= cyclohexyl (DBrCHMI) and n‐hexyl (DBrHMI)] and aryl boronic acid using palladium catalysts. To clarify structures of conjugated polymer containing maleimide units at the main chain, ¹³C NMR spectra of 2‐aryl or 2,3‐diaryl substituted maleimides were compared with those of N‐substituted maleimide polymers. Copolymers obtained with DBrRMI via Suzuki‐Miyaura cross‐coupling polymerizations or Yamamoto coupling polymerizations were dehalogenated structures at the terminal end. This dehalogenation may contribute to the low polymerizability of DBrRMIs. On the other hand, the π‐conjugated compounds showed high solubility in common organic solvents. The N‐substituents of maleimide cannot significantly affect the photoluminescence spectra of 2,3‐diaryl substituted maleimides derivatives. The fluorescence spectra of poly(RMI‐alt‐Ar) and poly(RMI‐co‐Ar) varied with N‐substituents of the maleimide ring. When exposed to ultraviolet light of wavelength 352 nm, a series of 1,4‐phenylene‐ and/or 2,5‐thienylene‐based copolymers containing N‐substituted maleimide derivatives fluoresced in a yellow to blue color. It was found that photoluminescence emissions and electronic state of π‐conjugated maleimide derivatives were controlled by aryl‐ and N‐substituents, and maleimide sequences of copolymers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Bulky side chain effect of poly(N‐vinylcarbazole)‐based stacked polymer electrets on device performance parameters of transistor memories

Three poly(N‐vinylcarbazole) (PVK)‐based polymer electrets were synthesized through Friedel‐Crafts postfunctionalization for the function of charge storage in nonvolatile organic field effect transistor (OFET) memory devices. The bulky side chain effect of these stacked polymer electrets on the morphology, water contact angles, and memory characteristics were examined with regard to those of precursor PVK. The introduction of steric hindrance groups could interrupt the large length of π‐stacked structures in PVK and block the form of region‐regular structures from region‐random on external electric field. As a result, the memories based on the three modified polymers exhibited approximate memory windows of 32 V increased by 13 V with respect to PVK. Besides, the write‐read‐erase‐read cycles stability of the modified polymers was superior to that of PVK. Furthermore, we found that the holes were mainly located in the region of local π‐stacked structures and bulky π‐conjugated groups also acted as additional electron trapping sites. Molecular engineering of charge trapping site with tunneling polymers will be a promise strategy for the advance of transistor memory. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3554–3564