Influence from Thermal Elimination Temperature of Precursor Polymer and Film‐forming Methods on the Photophysics of the Poly(2,5‐didodecyloxy‐p‐phenylenevinylene)

A series of poly(p‐phenylenevinylene)s (PPVs) with good solubility were synthesized from thermal elimination of precursor poly(2,5‐didodecyloxy‐p‐phenylenevinylene) at different temperature via Wessling method. The polymer photophysics were influenced by the thermal elimination condition, which was consistent with NMR and IR characterizations. The additional absorption peak at longer wavelength and the red‐shifted emission maximum both in solution and in film, for PPVs obtained at high elimination temperature, indicated the existence of longer conjugated blocks in these systems. The emission maximum for drop‐cast film (436 nm) for PPV obtained under 200°C (PPV200) was 16 nm blue shifted to the spin‐coated films (452 nm) or 29 nm to the solution (465 nm). The SEM study showed drop‐cast film had the morphology of isolated conjugated particles in the matrix while blurry linear structure was found for spin‐coated film, which was consistent with the photophysics. The discussion about this difference was carried out based on the consideration of the flexibility of the polymer chains and different conjugated length of PPV in different states.     

Electropolymerization of layer‐by‐layer precursor polymer films

The layer‐by‐layer (LbL) self‐assembly has been used to fabricate polymer thin films on any solid substrates. The multilayer polymer thin films are constructed by alternating adsorption of anionic and cationic polymers. Polyelectrolyte multilayer ultrathin films containing anionic poly[2‐(thiophen‐3‐yl)ethyl methacrylate‐co‐methacrylic acid]; P(TEM‐co‐MA) and cationic poly[4‐(9H‐carbazol‐9‐yl)‐N‐butyl‐4‐vinyl pyridium bromide]; P4VPCBZ, were fabricated. The growth of multilayer ultrathin films was followed by UV–Vis absorption spectrophotometer and surface plasmon resonance spectroscopy (SPR). The deposition of P(TEM‐co‐MA)/P4VPCBZ as multilayer self‐assembled ultrathin films regularly grow which showed linear growth of absorbance and thickness with increasing the number of layer pair. Cross‐linking of the layers was verified by cyclic voltammetry (CV), UV–Vis spectrophotometry and electrochemical surface plasmon resonance (EC‐SPR) spectroscopy with good electro‐copolymerizability. This was verified by spectroelectrochemistry. The SPR angular‐reflectivity measurement resulted in shifts to a higher reflectivity according to the change in the dielectric constant of the electropolymerized film. Copyright © 2011 John Wiley & Sons, Ltd.     

Dynamically Controllable Emission of Polymer Nanofibers: Electrofluorescence Chromism and Polarized Emission of Polycarbazole Derivatives

Electrochemical polymerization of a series of N‐alkyl‐2,7‐di(2‐thienyl)carbazoles in acetonitrile was performed to obtain conjugated polymers with fluorescence. Scanning electron and atomic force microscopies revealed that the surface morphology of the polymer films significantly depends on the alkyl chain lengths of the polymers. Particularly, a homopolymer bearing hexyl groups and copolymers with an average alkyl chain length of six carbon atoms show nanofiber morphology. The polymer nanofibers were stacked on a substrate electrode. The fluorescence of the polymer nanofiber film was tunable with application of voltage, with good repeatability. The X‐ray diffraction pattern of the fibers showed the structural order. The polymer nanofibers thus prepared showed an electrochemically driven change in polarized photoluminescence.     

Control of the conjugation length and solubility in electroluminescent polymers

A new type of cyclolinear polymer, poly(phenylene vinylene‐alt‐cyclotriphosphazene), was synthesized through Heck‐type coupling reactions to produce π‐conjugated macromolecules with excellent solubility and precise electronic control of the band‐gap energy. This synthesis method is capable of producing well‐defined alternating polymers. The method is highly adaptable and can be readily used for other chromophore systems. The resulting polymers were also capable of accommodating a wide variety of substituents on the cyclophosphazene rings with minimal effect on the electronic properties. The band gap and electron affinities of the polymer were varied through the manipulation of the π‐conjugated unit located between the insulating phosphazene rings. Each chromophore matched the intended conjugation length consistently throughout the macromolecules. The polymers were good film formers because of the chosen substituents on the phosphazene rings. The absorbance of the polymers indicated minimal spectral shift from the monomer absorbance. This suggested an effective insulation of each chromophore unit from its neighbors by the phosphazene rings. Solution photoluminescence efficiencies were found to be up to 44.1%. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 69–76, 2006     

Diffusion measurements using ATR‐FTIR spectroscopy: Acetone diffusion in polypropylene—use of penetrant fluid pressure to improve sample/IRE contact

In this article, we present a simple method for improving the contact between a film sample and the internal reflection element (or crystal) when diffusion into thin polymer films is measured with attenuated total reflectance (ATR)‐Fourier transform infrared spectroscopy. Intimate film/crystal contact is particularly important for making measurements on premade films and materials that cannot be solution‐coated onto the crystal. This method is based on controlling the penetrant fluid pressure above a threshold value (>230 kPa) in the ATR flow cell. Measurements of acetone diffusion into a commercial polypropylene film at 300 K and varied pressures indicated that the diffusion time constant was constant at pressures above this threshold. We also monitored the absorbance of a polymer band that had no overlap with the acetone spectrum to examine whether adequate sample‐film/crystal contact was reached and maintained. From these observations, we concluded that an apparently good match between the experimental data and a model calculation does not alone justify confidence in the accuracy of the calculated diffusion time constant. Additionally, the practice of using a reference band to correct the uncertainty in absorbance for bands of interest (due to imperfect sample/crystal contact) yielded inconsistent results. We also report further measurements of acetone diffusivity in a polypropylene film at temperatures ranging from 278 to 308 K that yielded an estimated activation energy for diffusion of 98 kJ/mol. © 2000 John Wiley & Sons, Inc.* J Polym Sci B: Polym Phys 38: 1773–1787, 2000     

Low‐potential facile electrosynthesis of free‐standing poly(1H‐benzo[g]indole) film as a yellow‐light‐emitter

High‐quality free‐standing poly(1H‐benzo[g]indole) (PBIn) films were synthesized electrochemically by direct anodic oxidation of 1H‐benzo[g]indole (BIn) in boron trifluoride diethyl etherate. PBIn films obtained from this medium showed good electrochemical behavior and better thermal stability with a conductivity of 0.29 S cm^?1. PBIn films with low band gap value (1.59 eV) were insoluble in acetone and tetrahydrofuran. The structure and morphology of the polymer were studied by UV–vis, FTIR, and scanning electron microscopy, respectively. The results of quantum chemistry calculations and the spectroscopies of dedoped PBIn indicate that the polymerization of BIn mainly occurs via C₍₂₎ and C₍₅₎ position. The polymer film was compact with regular nanoparticles on the surface. Fluorescent spectral studies indicate that solid‐state PBIn film is a good yellow‐light‐emitter. Thermal stability of PBIn film is higher than poly(indole‐6‐carboxylic acid), poly(5‐formylindole), and polyindole. To the best of our knowledge, this is the first report on the electrosynthesis of free‐standing polyindole derivatives as yellow‐light‐emitter. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2730–2738     

Donor–acceptor photovoltaic polymers based on 1,4‐dithienyl‐2,5‐dialkoxybenzene with intramolecular noncovalent interactions

Donor–acceptor (D–A) conjugated polymers bearing non‐covalent configurationally locked backbones have a high potential to be good photovoltaic materials. Since 1,4‐dithienyl‐2,5‐dialkoxybenzene ( TBT ) is a typical moiety possessing intramolecular S…O interactions and thus a restricted planar configuration, it was used in this work as an electron‐donating unit to combine with the following electron‐accepting units: 3‐fluorothieno[3,4‐b]thiophene ( TFT ), thieno‐[3,4‐c]pyrrole‐4,6‐dione ( TPD ), and diketopyrrolopyrrole ( DPP ) for the construction of such D–A conjugated polymers. Therefore, the so‐designed three polymers, PTBTTFT , PTBTTPD , and PTBTDPP , were synthesized and investigated on their basic optoelectronic properties in detail. Moreover, using [6,6]‐phenyl‐C₇₁‐butyric acid methyl ester (PC₇₁BM) as acceptor material, polymer solar cells (PSCs) were fabricated for studying photovoltaic performances of these polymers. It was found that the optimized PTBTTPD cell gave the best performance with a power conversion efficiency (PCE) of 4.49%, while that of PTBTTFT displayed the poorest one (PCE = 1.96%). The good photovoltaic behaviors of PTBTTPD come from its lowest‐lying energy level of the highest occupied molecular orbital (HOMO) among the three polymers, and good hole mobility and favorable morphology for its PC₇₁BM‐blended film. Although PTBTDPP displayed the widest absorption spectrum, the largest hole mobility, and regular chain packing structure when blended with PC₇₁BM, its unmatched HOMO energy level and disfavored blend film morphology finally limited its solar cell performance to a moderate level (PCE: 3.91%). © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 689–698     

Synthesis and characterization of novel nano size electroactive poly 4,4′‐diaminodiphenyl sulphone

The modification of electrodeposited polyaniline film by subsequent electrodeposition of 4,4′‐diaminodiphenyl sulfone (DDS) leads to a new material having nanostructure. The coated polymer films were treated with various pH solutions. The film adherent characteristics and surface morphology were studied using SEM. The electrochemically synthesized polyDDS revealed good redox behavior. The DDS was also polymerized by the chemical oxidation method using potassium persulphate. The polymer was characterized by UV‐Vis and FTIR spectral studies. The formation of polymer through the N? H group was understood from the single N? H stretching vibrational frequency at 3459 cm^?1. The X‐ray diffraction studies revealed the formation of nano sized (28 nm) crystalline polymer. The conductivity of the polymer was determined to be 1.07 × 10^?4 S.cm^?1. The solubility of the chemically polymerized powder was ascertained, and polyDDS showed good solubility in DMF and DMSO. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1702–1707, 2005     

Composite ultrafiltration membranes with tunable properties based on a self‐assembling block copolymer/homopolymer system

Composite ultrafiltration membranes were fabricated by coating a thin film of self‐assembling polystyrene‐block‐poly(ethylene oxide) (PS‐b‐PEO) block copolymers and poly(acrylic acid) homopolymers on top of a support membrane. Block copolymers self‐assembled into a nanostructure where the minority component forms cylinders, whereas homopolymers reside in the core of the cylinders. Selective removal of the homopolymers led to the formation of pores. The morphology of the polymer layer was controlled by varying the content of homopolymers or polymer concentration of the coating solution, which led to membranes with different molecular weight cutoffs (MWCOs) and permeabilities. Uniform pores were obtained using low homopolymer contents, whereas high homopolymer contents caused macrophase separation and resulted in large polydisperse pores or craters at the surface. The thickness of the block copolymer film also influenced the structure and performance of the membranes, where a thicker film results in a strong decrease in permeability but a lower MWCO. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1546–1558     

Synthesis of polymers containing regularly distributed tetrathia‐[7]‐elicene units along the backbone

A tetrathia‐[7]‐helicene bearing in the 2 and 13 positions cyanovinyl groups was used as comonomer in the Michael‐type polyaddition reaction with N,N′‐bis(β‐mercaptoethyl)piperazine. This led to a new polymer bearing tetrathia‐[7]‐helicene units regularly distributed along the polymer backbone, which may be regarded as the first example of a new family of potentially useful nonlinear optical materials. All products were structurally characterized by ¹H and ¹³C NMR spectroscopy. Differential scanning calorimetry characterizations revealed the presence, in both monomeric and polymeric helicenes, of glass‐transition like temperatures, associated to some conformational variation of the helicene units. The optical properties, the film formation and the morphology of the polymer‐containing tetratia‐[7]‐helicenes were also investigated. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Poly((2‐alkylbenzo[1,2,3]triazole‐4,7‐diyl)vinylene)s for organic solar cells

Poly((2‐Alkylbenzo[1,2,3]triazole‐4,7‐diyl)vinylene)s (pBTzVs) synthesized by Stille coupling show different absorption spectra, solid‐state morphology, and photovoltaic performance, depending on straight‐chain versus branched‐chain (pBTzV12 and pBTzV20) pendant substitution. Periodic boundary condition density functional computations show limited alkyl pendant effects on isolated chain electronic properties; however, pendants could influence polymer backbone conjugative planarity and polymer solid film packing. The polymers are electronically ambipolar, with best performance by pBTzV12 with hole and electron transport mobilities of 4.86 × 10^?6 and 1.96 × 10^?6 cm² V^?1 s^?1, respectively. pBTzV12 gives a smooth film morphology, whereas pBTzV20 gives a very different fibrillar morphology. For ITO/PEDOT:PSS/(1:1 w/w polymer:PC₇₁BM)/LiF/Al devices, pBTzV12 gives power conversion efficiency (PCE) up to 2.87%, and pBTzV20 gives up to PCE = 1.40%; both have open‐circuit voltages of V_OC = 0.6–0.7 V. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1539–1545     

Polystyrene‐b‐poly(2,2,2‐trifluoroethyl acrylate)‐b‐polystyrene copolymers: Synthesis and fabrication of their hydrophobic porous films,spheres, and fibers

New block copolymers Polystyrene‐b‐poly (2,2,2‐trifluoroethyl acrylate)‐b‐Polystyrene (PS‐PTFEA‐PS) with controlled molecular weight (M_n=5000‐11000 g?mol^?1) and narrow molecular weight distribution (M_w/M_n=1.13‐1.17) were synthesized via RAFT polymerization. The molecular structure and component of PS‐PTFEA‐PS block copolymers were characterized through ¹H NMR, ¹⁹F NMR, GPC, FT‐IR and elemental analysis. The porous films of such copolymers with average pore size of 0.80‐1.34 μm and good regularity were fabricated via a static breath‐figure (BF) process. The effects of solvent, temperature, and polymer concentration on the surface morphology of such film were investigated. In addition, microstructured spheres and fibers of such block copolymers were fabricated by electrospinning process and observed by scanning electron microscopy (SEM). Furthermore, the hydrophobicity of porous films, spheres, and fibers was investigated. The porous film showed a good hydrophobicity with the water‐droplet contact angles of 129°, and the fibers showed higher hydrophobicity with the water‐droplet contact angles of 142°. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 678–685     

Microdomain morphology of lamella‐forming diblock copolymer confined in a thin film

We report the self‐consistent field theory (SCFT) of the morphology of lamella‐forming diblock copolymer thin films confined in two horizontal symmetrical/asymmetrical surfaces. The morphological dependences of thin films on the polymer‐surface interactions and confinement, such as film thickness and confinement spatial structure, have been systematically investigated. Mechanisms of the morphological transitions can be understood mainly through the polymer‐surface interactions and confinement entropy, in which the plat confinement surface provides a surface‐induced effect. The confinement is expressed in the form of the ratio D/L₀, here D is film thickness, and L₀ is the period of bulk lamellar‐structure. Much richer morphologies and multiple surface‐induced morphological transitions for the lamella‐forming diblock copolymer thin films are observed, which have not been reported before. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1–10, 2009     

Color tunability in non‐doped single‐layer PLEDs from a carbazole‐based electroluminescent polymer

A conjugated polymer with a carbazole moiety, poly(3,6‐divinylene‐N‐octyl‐carbazole‐p‐phenylene), was synthesized by Wittig reaction. The polymer can be dissolved in common organic solvents such as THF, chloroform, etc. Using this polymer as an active layer, single‐layer non‐doped PLEDs with different thicknesses were fabricated by a spin‐coating approach. The results suggested that electroluminescence spectra are changed with the film thickness of the polymer emitter. Fortunately, CIE 1931 coordinate values are moved to the white‐light region only by changing the film thickness. Copyright © 2008 John Wiley & Sons, Ltd.     

Soluble,saturated‐red‐light‐emitting poly(p‐phenylenevinylene) containing triphenylamine units and cyano groups

A conjugated poly(p‐CN‐phenylenevinylene) (PCNPV) containing both electron‐donating triphenylamine units and electron‐withdrawing cyano groups was prepared via Knoevenagel condensation in a good yield. Gel permeation chromatography suggested that the soluble polymer had a very high weight‐average molecular weight of 309,000. A bright and saturated red emission was observed under UV excitation in solution and film. Cyclic voltammetry showed that the polymer presented quasi‐reversible oxidation with a relatively low potential because of the triphenylamine unit. A single‐layer indium tin oxide/PCNPV/Mg–Ag device emitted a bright red light (633 nm). © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3947–3953, 2004     

Conjugated block copolymers via functionalized initiators and click chemistry

Conjugated block copolymers are potentially useful for organic electronic applications and the study of interfacial charge and energy transfer processes; yet few synthetic methods are available to prepare polymers with well‐defined conjugated blocks. Here, we report the synthesis and thin film morphology of a series of conjugated poly(3‐hexylthiophene)‐block‐poly(9,9‐dioctylfluorene) (P3HT‐b‐PF) and poly(3‐dodecylthiophene)‐block‐poly(9,9‐dioctylfluorene) (P3DDT‐b‐PF) block copolymers prepared by functional external initiators and click chemistry. Functional group control is quantified by proton nuclear magnetic resonance spectroscopy, size‐exclusion chromatography, and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. The thin film morphology of the resulting all‐conjugated block copolymers is analyzed by a combination of grazing‐incidence X‐ray scattering, atomic force microscopy, and transmission electron microscopy. Crystallization of the P3HT or P3DDT blocks is present in thin films for all materials studied, and P3DDT‐b‐PF films exhibit significant PF/P3DDT co‐crystallization. Processing conditions are found to impact thin film crystallinity and orientation of the π–π stacking direction of polymer crystallites. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 154–163     

Decreased domain size and improved crystallinity by adjusting solvent–polymer interaction parameters in all‐polymer solar cells

We have investigated the effect of solvent–polymer interaction on the morphology, crystallinity, and device performance of poly‐(3‐hexylthiophene) (P3HT) and poly{2,7‐(9,9‐didodecyl‐fluorene)‐alt‐5,5‐[4′,7′‐bis(2‐thienyl)‐2′,1′,3′‐benzothia‐diaole]} (PF12TBT) blend system. 3‐Hexylthiophene (3‐HT), which had the similar structural units with both donor and acceptor materials, was chosen as the solvent additive to be added into the main solvent chlorobenzene (CB), to adjust the solvent–polymer interaction. With the 3‐HT percentage increasing from 5 to 30% in CB solution, the solvent–polymer interaction between polymer and solvent molecules decreased slightly according to the calculated solubility parameters (δ) and interaction parameters (χ₁₂). As a result, nanoscale phase‐separated and interconnected morphology with decreased domain size of both donor and acceptor was formed. Meanwhile, the order of P3HT molecule was enhanced which resulted from the extended film drying time and increased molecular planarity after incorporation of 3‐HT. The power conversion efficiency (PCE) had a gradual improvement to 1.08% as the 3‐HT percentage reached 10%, which can be attributed to the enhanced short‐circuit current (J_sc) and fill factor (FF). However, when the 3‐HT percentage exceeded 20%, the decreased J_sc and FF ultimately decreased the PCE. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 288–296     

Solvent‐induced reversible color changes in block copolymer films and new locking method of structural colors

The well‐defined polystyrene‐block‐poly(4‐vinylpyridine) [PS‐block‐P4VP (SV1); lamellar morphology] and polyisoprene‐block‐poly(α‐methyl styrene) [PI‐block‐PMS (IMS1); PI spherical morphology] diblock copolymers were prepared by sequential anionic polymerization techniques. The segregated chains in the P4VP lamellar layers of the SV1 film (PS lamellae: 41 nm; P4VP lamellae: 51 nm) were crosslinked with 1,4‐dibromobutane. This crosslinked film was insoluble in organic solvents such as benzene and chloroform (CHCl₃) and exhibited various structural colors under the swollen state. The IMS1 film (body‐centered cubic lattice, diameter of PI spheres: 53 nm) was soaked in the mixture of CHCl₃/hexane (1 : 10, v/v). This solvent system resulted in the swelling of PI spherical domains. The transmitted and reflected light color through the swollen film changed to a deep blue. Such color changes were reversible upon swelling in solvent and evaporation of the solvent. Subsequently, photofunctional diethyldithiocarbamate (DC) groups were introduced into the PS block of the parent block copolymer IMS1 by means of polymer reactions. The locking of the cubic lattice was performed with living radical graft copolymerization from DC groups of swollen as‐cast film in methyl methacrylate (MMA) under UV irradiation. The locking of structural colors such as blue and green was also achieved, varying the content of poly(methyl methacrylate) (PMMA) grafted chains. Copyright © 2005 John Wiley & Sons, Ltd.     

Diketopyrrolopyrrole‐based polymer fibrils formation by changing molecular conformation during film formation

The microstructure of conjugated polymers film is strongly dependent on factors such as the conformation and the film formation processing. In this article, we show how to induce more planarization conformation of conjugated polymer backbone during film formation processing and finally leading to the fibrils formation of the cast film. The conjugated polymer we used is poly[[2,5‐bis(2‐octyldodecyl)‐2,3,5,6‐tetrahydro‐3,6‐dioxopyrrolo[3,4‐c]pyrrole‐1,4‐diyl]‐alt–[[2,2′‐(2,5‐thiophene)bis‐thieno[3,2‐b]thiophen]‐5,5′‐diyl]] (PDPPTT‐T). The main solvent is chloroform (CF), the aliphatic 1,8‐diiodooctane (DIO) is used as the additives, which has similar solubility parameter to the conjugated polymer side chain, is a bad solvent to the conjugated backbone and has a lower volatility than CF. Thus, during the film formation, chloroform was evaporated faster than the additive. After the chloroform evaporated completely, the side chain was still dissolved in the additive, which decreases the steric hindrance and improves planarization conformation of the conjugated backbone of PDPPTT‐T. Films processed using the aliphatic additives have fibrillar morphology while films cast from the CF solvent were featureless. TEM images reveal that the fibrils were about 30 nm in width and several hundred nanometers in length. The backbones of PDPPTT‐T were parallel to the long axis of fibrils. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 1079–1086     

Electro‐optical properties of electropolymerized poly(3‐hexylthiophene)/carbon nanotube composite thin films

3‐hexylthiophene was electropolymerized on a carbon nanotube (CNT)‐laden fluorine‐doped tin oxide substrate. Scanning electron microscopy and Raman spectroscopy revealed that the polymer was infused throughout the thickness of the 150‐nm thick CNT mat, resulting in a conducting composite film with a dense CNT network. The electropolymerized poly(3‐hexylthiophene) (e‐P3HT)/CNT composites exhibited photoluminescence intensity quenching by as much as 92% compared to the neat e‐P3HT, which provided evidence of charge transfer from the polymer phase to the CNT phase. Through‐film impedance and J‐V measurements of the composites gave a conductivity (σ) of 1.2 × 10^?10 S cm^?1 and zero‐field mobility (μ₀) of 8.5 × 10^?4 cm² V^?1 s^?1, both of which were higher than those of neat e‐P3HT films (σ = 9.9 × 10^?12 S cm^?1, μ₀ = 3 × 10^?5 cm² V^?1 s^?1). In electropolymerized samples, the thiophene rings were oriented in the (010) direction (thiophene rings parallel to substrate), which resulted in a broader optical absorbance than for spin coated samples, however, the lack of long‐range conjugation caused a blueshift in the absorbance maximum from 523 nm for unannealed regioregular P3HT (rr‐P3HT) to 470 nm for e‐P3HT. Raman spectroscopy revealed that π‐π stacking in e‐P3HT was comparable to that in rr‐P3HT and significantly higher than in regiorandom P3HT (ran‐P3HT) as shown by the principal Raman peak shift from 1444 to 1446 cm^?1 for e‐P3HT and rr‐P3HT to 1473 cm^?1 for ran‐P3HT. This work demonstrates that these polymer/CNT composites may have interesting properties for electro‐optical applications. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1269–1275, 2011