Showing papers on "Side chain published in 2008"
TL;DR: The synthesis, self-assembly, and gelation ability of a series of organogelators based on perylene bisimide (PBI) dyes containing amide groups at imide positions are reported, which points to a self-sorting process.
Abstract: The synthesis, self-assembly, and gelation ability of a series of organogelators based on perylene bisimide (PBI) dyes containing amide groups at imide positions are reported. The synergetic effect of intermolecular hydrogen bonding among the amide functionalities and pi-pi stacking between the PBI units directs the formation of the self-assembled structure in solution, which beyond a certain concentration results in gelation. Effects of different peripheral alkyl substituents on the self-assembly were studied by solvent- and temperature-dependent UV-visible and circular dichroism (CD) spectroscopy. PBI derivatives containing linear alkyl side chains in the periphery formed H-type pi stacks and red gels, whereas by introducing branched alkyl chains the formation of J-type pi stacks and green gels could be achieved. Sterically demanding substituents, in particular, the 2-ethylhexyl group completely suppressed the pi stacking. Coaggregation studies with H- and J-aggregating chromophores revealed the formation of solely H-type pi stacks containing both precursor molecules at a lower mole fraction of J-aggregating chromophore. Beyond a critical composition of the two chromophores, mixed H-aggregate and J-aggregate were formed simultaneously, which points to a self-sorting process. The versatility of the gelators is strongly dependent on the length and nature of the peripheral alkyl substituents. CD spectroscopic studies revealed a preferential helicity of the aggregates of PBI building blocks bearing chiral side chains. Even for achiral PBI derivatives, the utilization of chiral solvents such as (R)- or (S)-limonene was effective in preferential population of one-handed helical fibers. AFM studies revealed the formation of helical fibers from all the present PBI gelators, irrespective of the presence of chiral or achiral side chains. Furthermore, vortex flow was found to be effective in macroscopic orientation of the aggregates as evidenced from the origin of CD signals from aggregates of achiral PBI molecules.
396 citations
TL;DR: A new light-emitting polyacetylene bearing imidazole moieties in the side chain was conveniently prepared through a postfunctionalization strategy, as a sensory polymer to selectively report the presence of Cu2+ based on the fluorescence "turn-off".
290 citations
TL;DR: In this paper, the whisker method using anisole solvent was developed for effective production of high-aspect-ratio poly (3-alkylthiophene) (P3AT) nanofibers, and alkyl chain length dependence on nanofiber formation and their properties were fully investigated.
Abstract: The whisker method using anisole solvent was developed for effective production of high-aspect-ratio poly (3-alkylthiophene) (P3AT) nanofibers, and alkyl chain length dependence on nanofiber formation and their properties were fully investigated. The nanofibers have an anisotropic cross section of 3−4 nm height and 24−27 nm width, which slightly increase with the alkyl chain length, and the aspect ratio reaches 100−1000. The nanofibers consist of more than 104 parallel stacks of the extended polymer backbones along the nanofiber long axis and of 2−3 laminated layers of the polymer backbones separated by alkyl side chains. The nanofiber formation originates from quasi-one-dimensional crystallization of P3ATs induced by both an attractive π−π* interaction between polymer backbones and the crystallization of alkyl side chains. Carrier transport properties of a AuCl3-doped nanofiber network and single nanofibers, both of which are explained by a quasi-one-dimensional variable-range hopping (VRH) model irrespe...
262 citations
TL;DR: In this article, the authors investigated the primary biodegradation of different N-imidazoles, imidazolium, pyridinium, and 4-(dimethylamino)pyrinium compounds substituted with various alkyl side chains and their analogues containing functional groups.
227 citations
TL;DR: In this article, the synthesis and performance of new methacrylate ester based polycarboxylate superplasticizers is compared to those of conventional ones, which possess hydroxy termination of the poly(ethylene glycol) side chains instead of conventional methoxy termination.
220 citations
TL;DR: The introduction of polar hydroxy, ether or nitrile functions into the alkyl side chain is shown to be a potent structural alteration to shift the corresponding ionic liquids to a lower inhibitory potential.
177 citations
TL;DR: Detailed factors influencing the relationship between structure and gene delivery properties are presented and may provide helpful insights for the further development of safe and efficient non-viral vectors.
161 citations
TL;DR: In this paper, a chain collapse of linear polymers driven by noncovalent cross-linking of dendritic self-complementary hydrogen-bonding units (SHB) was investigated.
Abstract: Novel polymeric nanoparticles were prepared through the chain collapse of linear polymers driven by noncovalent cross-linking of dendritic self-complementary hydrogen-bonding units (SHB). Random copolymers containing SHB units, poly[(methyl methacrylate)-r-2-((3,5-bis(4-carbamoyl-3-(trifluoromethyl)phenoxy)benzyloxy)carbonylamino)ethyl methacrylate] (A1, A2), were synthesized with various incorporation ratios by reversible addition−fragmentation chain transfer (RAFT) polymerization. Dramatically different behavior was observed depending on the level of incorporation of the supramolecular units. At high loadings of A2 (6% SHB incorporation), intramolecular chain collapse is favored, resulting in the formation of well-defined polymer nanoparticles, which were characterized by scanning force microscopy (SFM), dynamic light scattering (DLS), and viscosity studies. In contrast, analysis of copolymer A1 (1% SHB incorporation) revealed that chain collapse occurred primarily through intermolecular interactions le...
152 citations
TL;DR: The present result appears to represent the first effort toward controlling and tuning the morphology of self-assembled nanostructures of porphyrin derivatives via molecular design and synthesis through introduction of metal-ligand coordination bonding interaction.
Abstract: Novel metal-free 5,15-di[4-(5-acetylsulfanylpentyloxy)phenyl]porphyrin H2[DP(CH3COSC5H10O)2P] (1) and its zinc congener Zn[DP(CH3COSC5H10O)2P] (2) were designed and synthesized. Single-crystal X-ray diffraction (XRD) analysis confirmed the tetrapyrrole nature of these two compounds, revealing the existence of metal−ligand coordination bond between the carbonyl oxygen in the aryloxy side chain of meso-attached phenyl group in the porphyrin molecule with the zinc center of neighboring porphyrin molecule in the crystal structure of 2. This intermolecular Zn−O coordination bond induces the formation of a supramolecular chain structure in which the porphyrinato zinc moieties are arranged in a “head-to-tail” mode (J-aggregate), which is in contrast to a “face-to-face” stacking mode (H-aggregate) in the supramolecular structure formed depending on the C−H···π interaction in the crystal of 1. Their self-assembling properties in MeOH and n-hexane were comparatively investigated by scanning electronic microscopy an...
143 citations
TL;DR: In this paper, a polythiophene (PT)-based molecular brush (PT-g-PDMA) was synthesized by growing poly(N,N-dimethylaminoethyl methacrylate) chains from the PT backbone by ATRP.
Abstract: We report the synthesis of a new polythiophene (PT)-based molecular brush (PT-g-PDMA) by growing poly(N,N-dimethylaminoethyl methacrylate) (PDMA) chains from the PT backbone by ATRP The polymer shows a reversible pH response in aqueous solution A combination of AFM, light scattering, and 1H NMR measurements indicated that the polymer brush forms a more extended conformation with a decrease in pH from 8 to 2 due to the protonation of the Me2N− groups and increased repulsive interactions among the PDMA side chains, which drives the red shift of the absorption and PL spectra of the PT backbone The good solubility of this polythiophene-based brush in a wide range of solvents is attractive for the fabrication of functional polymer composites
138 citations
TL;DR: The findings represent a significant step toward the evolution of sequence-defined synthetic polymers and also demonstrate that enzyme-free nucleic acid-templated polymerization can occur efficiently using substrates with a wide range of side-chain structures, functionalization positions within each building block, and functionalization densities.
Abstract: The DNA-templated polymerization of synthetic building blocks provides a potential route to the laboratory evolution of sequence-defined polymers with structures and properties not necessarily limited to those of natural biopolymers. We previously reported the efficient and sequence-specific DNA-templated polymerization of peptide nucleic acid (PNA) aldehydes. Here, we report the enzyme-free, DNA-templated polymerization of side-chain-functionalized PNA tetramer and pentamer aldehydes. We observed that polymerization of tetramer and pentamer PNA building blocks with a single lysine-based side chain at various positions in the building block could proceed efficiently and sequence specifically. In addition, DNA-templated polymerization also proceeded efficiently and in a sequence-specific manner with pentamer PNA aldehydes containing two or three lysine side chains in a single building block to generate more densely functionalized polymers. To further our understanding of side-chain compatibility and expand the capabilities of this system, we also examined the polymerization efficiencies of 20 pentamer building blocks each containing one of five different side-chain groups and four different side-chain regio- and stereochemistries. Polymerization reactions were efficient for all five different side-chain groups and for three of the four combinations of side-chain regio- and stereochemistries. Differences in the efficiency and initial rate of polymerization correlate with the apparent melting temperature of each building block, which is dependent on side-chain regio- and stereochemistry but relatively insensitive to side-chain structure among the substrates tested. Our findings represent a significant step toward the evolution of sequence-defined synthetic polymers and also demonstrate that enzyme-free nucleic acid-templated polymerization can occur efficiently using substrates with a wide range of side-chain structures, functionalization positions within each building block, and functionalization densities.
TL;DR: The vibrational frequencies of the amide-I modes, freed from effects of amide vibrational excitation exchange by 5% dilution experiments, point to there being a component of an electric field along the fibril axis that increases through the sequence Gly-38, Gly-33, Gly -29, the field is dominated by side chains of neighboring residues.
Abstract: The 2D IR spectra of the amide-I vibrations of amyloid fibrils from Aβ40 were obtained. The matured fibrils formed from strands having isotopic substitution by 13 C= 18 O at Gly-38, Gly-33, Gly-29, or Ala-21 show vibrational exciton spectra having reduced dimensionality. Indeed, linear chain excitons of amide units are seen, for which the interamide vibrational coupling is measured in fibrils grown from 50% and 5% mixtures of labeled and unlabeled strands. The data prove that the 1D excitons are formed from parallel in-register sheets. The coupling constants show that for each of the indicated residues the amide carbonyls in the chains are separated by 0.5 ± 0.05 nm. The isotope replacement of Gly-25 does not reveal linear excitons, consistent with the region of the strand having a different structure distribution. The vibrational frequencies of the amide-I modes, freed from effects of amide vibrational excitation exchange by 5% dilution experiments, point to there being a component of an electric field along the fibril axis that increases through the sequence Gly-38, Gly-33, Gly-29. The field is dominated by side chains of neighboring residues.
TL;DR: The stabilizing effect of the heteroatom directly attached to the intermediate arene oxides led to highly selective reactions, even in the case of only mono-substituted furans, which is quite different from previous results obtained with non-heteroatom-subStituted alkynes.
Abstract: Different furans containing an ynamide or alkynyl ether moiety in the side chain were prepared. The gold-catalyzed transformation of these compounds delivered dihydroindole, dihydrobenzofuran, chroman, and tetrahydroquinoline derivatives at room temperature through very fast reactions. Furthermore, the stabilizing effect of the heteroatom directly attached to the intermediate arene oxides led to highly selective reactions, even in the case of only mono-substituted furans, which is quite different from previous results obtained with non-heteroatom-substituted alkynes.
TL;DR: The data indicate that some of these branched oleochemicals have significant potential as a lubricating oil or fuel additives.
TL;DR: 1H NMR and FTIR proved the presence of these functional groups and the ability for the introduction of an elevated and controllable amount of functional groups that do not interfere with the PU chemistry.
Abstract: Linear polyurethanes (PUs) having alkyne groups located along the backbone have been synthesized by reacting two different alkyne-functionalized diols with a diisocyanate compound. 1H NMR and FTIR proved the presence of these functional groups and the ability for the introduction of an elevated and controllable amount of functional groups that do not interfere with the PU chemistry. TGA measurements demonstrated that the incorporated alkyne diol in the PU materials strongly improves the final char yield. In the second part of the work, the copper catalyzed Huisgen 1,3-dipolar cycloaddition was undertaken between the alkyne-functionalized PUs and a variety of azide compounds such as benzyl azide and different fluorinated azide compounds, resulting in side-chain functionalized PUs with varying degree of functionalization. 1H NMR spectra clearly indicated the quantitative yields of the “click” reaction.
TL;DR: The RMSD of the present approach improves if one considers only strongly shifted pK Aexp in contrast to the other methods under these conditions, and the method allows interpreting pK’s in terms of pH dependent hydrogen bonding pattern and salt bridge geometries.
Abstract: pK(A) in proteins are determined by electrostatic energy computations using a small number of optimized protein conformations derived from crystal structures. In these protein conformations hydrogen positions and geometries of salt bridges on the protein surface were determined self-consistently with the protonation pattern at three pHs (low, ambient, and high). Considering salt bridges at protein surfaces is most relevant, since they open at low and high pH. In the absence of these conformational changes, computed pK(A)(comp) of acidic (basic) groups in salt bridges underestimate (overestimate) experimental pK(A)(exp), dramatically. The pK(A)(comp) for 15 different proteins with 185 known pK(A)(exp) yield an RMSD of 1.12, comparable with two other methods. One of these methods is fully empirical with many adjustable parameters. The other is also based on electrostatic energy computations using many non-optimized side chain conformers but employs larger dielectric constants at short distances of charge pairs that diminish their electrostatic interactions. These empirical corrections that account implicitly for additional conformational flexibility were needed to describe the energetics of salt bridges appropriately. This is not needed in the present approach. The RMSD of the present approach improves if one considers only strongly shifted pK(A)(exp) in contrast to the other methods under these conditions. Our method allows interpreting pK(A)(comp) in terms of pH dependent hydrogen bonding pattern and salt bridge geometries. A web service is provided to perform pK(A) computations.
TL;DR: Side chain analog and transmembrane helix models are employed to determine the free energy of an Arg side chain, as a function of protonation state, across a membrane, suggesting that although Arg side chains are ideally suited for carrying charge, the thermodynamics dictate that they must remain sequestered from the lipid bilayer environment.
Abstract: The issue of ionizable protein side chains interacting with lipid membranes has been the focus of much attention since the proposal of the paddle model of voltage-gated ion channels, which suggested multiple arginine (Arg) side chains may move through the hydrocarbon core of a lipid membrane. Recent cell biology experiments have also been interpreted to suggest that these side chains would face only small free energy penalties to cross membranes, challenging a long-standing view in membrane biophysics. Here, we employ side chain analog and transmembrane helix models to determine the free energy of an Arg side chain, as a function of protonation state, across a membrane. We observe high free energy barriers for both the charged and neutral states that would prohibit lipid-exposed movement. The mechanisms for charged and neutral Arg transport are, however, very different, with the neutral state experiencing simple dehydration, whereas the charged state experiences a complex mechanism involving connections to the bilayer interfaces that deform the local membrane structure. We employ special methods to ensure sampling of these interfacial connections and decompose the free energy to shed light on the mechanisms. These deformations are found to preferentially stabilize the protonated form, such that the Arg side chain remains almost exclusively charged inside the membrane, with a pKa shift of <4.5 units. In contrast, the analog models are found to exaggerate the variations in energetics across the membrane and have larger pKa shifts. These results have implications for models of voltage gated ion channels, suggesting that although Arg side chains are ideally suited for carrying charge, the thermodynamics dictate that they must remain sequestered from the lipid bilayer environment.
TL;DR: The results showed that an ideal brush layer structure with the adsorbed polymers adopting comb-like conformation is not necessary for achieving a low coefficient of friction in the asymmetric mica-silica system.
Abstract: The effect of side chain to charge ratio on the frictional properties of adsorbed layers formed by bottle-brush polyelectrolytes with poly(ethylene oxide) side chains has been investigated. The bru ...
TL;DR: The 2′OH is a major player inprotein–RNA recognition, and shape complementarity an important determinant, whereas electrostatics and direct base–protein interactions play a lesser part than in protein–DNA recognition.
Abstract: We analyze the protein-RNA interfaces in 81 transient binary complexes taken from the Protein Data Bank. Those with tRNA or duplex RNA are larger than with single-stranded RNA, and comparable in size to protein-DNA interfaces. The protein side bears a strong positive electrostatic potential and resembles protein-DNA interfaces in its amino acid composition. On the RNA side, the phosphate contributes less, and the sugar much more, to the interaction than in protein-DNA complexes. On average, protein-RNA interfaces contain 20 hydrogen bonds, 7 that involve the phosphates, 5 the sugar 2'OH, and 6 the bases, and 32 water molecules. The average H-bond density per unit buried surface area is less with tRNA or single-stranded RNA than with duplex RNA. The atomic packing is also less compact in interfaces with tRNA. On the protein side, the main chain NH and Arg/Lys side chains account for nearly half of all H-bonds to RNA; the main chain CO and side chain acceptor groups, for a quarter. The 2'OH is a major player in protein-RNA recognition, and shape complementarity an important determinant, whereas electrostatics and direct base-protein interactions play a lesser part than in protein-DNA recognition.
TL;DR: In this article, the authors identify the molecular origin of mesophase transition as the melting of interdigitated linear alkane side chains, in this case quaterdecyl.
Abstract: The carrier mobility of poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene) semiconductors can be substantially enhanced after heating through a thermotropic mesophase transition, which causes a significant improvement in thin film structural order. By directly measuring film structure throughout a heating and cooling cycle, we identify the molecular origin of this mesophase transition as the melting of interdigitated linear alkane side chains, in this case quaterdecyl. The morphology and phase behavior throughout the thermal cycle are controlled by the changing conformation of the side chains. Surprisingly, the melting of the side chains allows increases in the backbone order, p-p stacking, and carrier mobility. Upon cooling, the side chains recrystallize to preserve the excellent mesophase order and enhanced electrical performance.
TL;DR: In this article, the influence of Cγ-OH on pyrolytic cleavage mechanism of β-ether-linkage in lignin dimer was studied in N2 with Cγdeoxy-type dimers, which have various p-substituents (H, Cl, OCH3) at their Cβ-phenoxy groups.
TL;DR: It is found that cyclically constrained β-amino acid residues can stabilize the folds of α/β-peptide GCN4-pLI analogues and restore quaternary structure formation to backbones that are predominantly unfolded in the absence of cyclic residues.
Abstract: The extent to which polypeptide conformation depends on side-chain composition and sequence has been widely studied, but less is known about the importance of maintaining an α-amino acid backbone. Here, we examine a series of peptides with backbones that feature different repeating patterns of α- and β-amino acid residues but an invariant side-chain sequence. In the pure α-backbone, this sequence corresponds to the previously studied peptide GCN4-pLI, which forms a very stable four-helix bundle quaternary structure. Physical characterization in solution and crystallographic structure determination show that a variety of α/β-peptide backbones can adopt sequence-encoded quaternary structures similar to that of the α prototype. There is a loss in helix bundle stability upon β-residue incorporation; however, stability of the quaternary structure is not a simple function of β-residue content. We find that cyclically constrained β-amino acid residues can stabilize the folds of α/β-peptide GCN4-pLI analogues and restore quaternary structure formation to backbones that are predominantly unfolded in the absence of cyclic residues. Our results show a surprising degree of plasticity in terms of the backbone compositions that can manifest the structural information encoded in a sequence of amino acid side chains. These findings offer a framework for the design of nonnatural oligomers that mimic the structural and functional properties of proteins.
TL;DR: An amorphous, flexible, and sufficiently tough elastomer film was prepared by crosslinking the obtained SGC-a supramolecule possessing a number of mobile side chains-with hexamethylene diisocyanate (HMDI).
Abstract: A novel “sliding graft copolymer” (SGC), in which many linear poly-e-caprolactone (PCL) side chains are bound to cyclodextrin rings of a polyrotaxane, was prepared by ring-opening polymerization of e-caprolactone initiated by hydroxyl groups of the polyrotaxane. An amorphous, flexible, and sufficiently tough elastomer film was prepared by crosslinking the obtained SGC—a supramolecule possessing a number of mobile side chains—with hexamethylene diisocyanate (HMDI).
TL;DR: Crystal structures have been determined for T4 lysozyme bearing a nitroxide side chain (R1) at the solvent‐exposed helical sites 41 and 44 in the B helix and suggest intrahelical interactions of 41R1 with the i + 4 residue and of 44R1WithThe i + 1 residue appear to be specific to particular rotamers of the R1 side chain.
Abstract: Site-directed spin labeling provides a means for exploring structure and dynamics in proteins. To interpret the complex EPR spectra that often arise, it is necessary to characterize the rotamers of the spin-labeled side chain and the interactions they make with the local environment in proteins of known structure. For this purpose, crystal structures have been determined for T4 lysozyme bearing a nitroxide side chain (R1) at the solvent-exposed helical sites 41 and 44 in the B helix. These sites are of particular interest in that the corresponding EPR spectra reveal two dynamic states of R1, one of which is relatively immobilized suggesting interactions of the nitroxide with the environment. The crystal structures together with the effect of mutagenesis of nearest neighbors on the motion of R1 suggest intrahelical interactions of 41R1 with the i + 4 residue and of 44R1 with the i + 1 residue. Such interactions appear to be specific to particular rotamers of the R1 side chain.
TL;DR: This paper demonstrates both theoretically and experimentally that in this particular case the relaxation profiles are, in excellent approximation, monoexponential, and suggests that the entire dynamic network, including motions of side chains in the protein hydrophobic core and backbone motions, is similar.
Abstract: In this paper, we seek to compare the internal dynamics of a small globular protein, SH3 domain from α-spectrin, in solution and in a crystalline state. The comparison involves side-chain methyl 13C R1 relaxation rates that are highly sensitive to local dynamics in the vicinity of the methyl site. To conduct the relaxation measurements, protein samples have been prepared using specially labeled α-ketoisovalerate precursors, resulting in selective incorporation of the 1H−13C spin pair in one or both methyl groups of the valine and leucine side chains. The sparse labeling pattern in an otherwise deuterated sample makes it possible to record high-resolution 13C, 1H solid-state spectra using magic angle spinning experiment with a MAS frequency of 22 kHz. Furthermore, this labeling scheme avoids proton-driven 13C−13C spin-diffusion effects, thus allowing for accurate measurements of 13C R1 relaxation in the individual methyl groups. While the relaxation response from a polycrystalline sample is generally expec...
TL;DR: A series of polyvinylidene fluoride)-g-sulfonated polystyrene graft copolymers were systematically synthesized and examined with the focus of understanding how the polymer microstructure (backbone molecular weight, graft density, graft length, sulfonic acid concentration, ion exchange capacity, etc.) affects their morphology, water uptake, and proton conductivity under various environmental conditions (temperature and relative humidity) as mentioned in this paper.
Abstract: A series of poly(vinylidene fluoride)-g-sulfonated polystyrene (PVDF-g-SPS) graft copolymers were systematically synthesized and examined with the focus of understanding how the polymer microstructure (backbone molecular weight, graft density, graft length, sulfonic acid concentration, ion exchange capacity, etc.) affects their morphology, water uptake, and proton conductivity under various environmental conditions (temperature and relative humidity). The synthesis of these relatively well-defined graft structures involves three reaction steps, including the preparation of PVDF copolymers containing a few mol% of chlorotrifluoroethylene (CTFE) units, the ATRP graft-from reaction to incorporate several polystyrene side chains, and the subsequent sulfonation reaction on the PS side chains. The PVDF-g-SPS graft copolymer with a combination of a high PVDF backbone molecular weight (Mn >300 000 g/mol), very low SPS graft density (0.3 mol%), and high graft length (SPS content >30 mol%) presents an interesting m...
TL;DR: In this article, the desorption of CO2 from saturated solvents at 80 °C and atmospheric pressure was measured to assess the initial Desorption rate and desorptive capacities at pseudo-equilibrium.
TL;DR: In this article, a series of soluble polythiophene derivatives containing triphenylamine moiety were synthesized by Grignard metathesis (GRIM) method and their physical properties were investigated.
Abstract: A series of novel soluble polythiophene derivatives containing triphenylamine moiety were synthesized by Grignard metathesis (GRIM) method. The structures of the polymers were characterized and their physical properties were investigated. High molecular weight (Mn up to 25,800 g/mol) and thermostable polymers were obtained. The absorption spectra demonstrated that the absorption wavelength of the polymers could be tuned dramatically by introducing thiophene units in the main chain of the polymers. Photoluminescence spectra indicated that there was intramolecular energy transfer from the side chain to the main chain, and the maximum emission was red-shifted gradually with the increase of thiophene units in the main chain. Cyclic voltammetry displayed that the polymers possessed relatively high oxidation potential, which promised good air stability and high open circuit voltage for photovoltaic cells application. Finally, bulk heterojunction photovoltaic devices were fabricated by using the polymers as donors and (6,6)-phenyl C61-butyric acid methyl ester (PCBM) as acceptor. The maximal open circuit voltage of the photovoltaic cells reached 0.71–0.87 V and the power conversion efficiencies of the devices were measured between 0.014% and 0.45% under white light at 100 mW/cm2. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3970–3984, 2008