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Applying Scanning Probe Microscopy (SPM) methods to determine structural details of biomolecules (e.g. proteins) is one of the key trends in nanotechnology. Here we present the analysis of a Langmuir-Blodgett film of hydrofobin HFBI. The statistical analysis is based on an accurate procedure of data detrending to study the quasi-crystalline clusters of the HFBI layer. A statistical improvement method of signal to noise ratio was used. It relies on the variation of the crystallographic lattice superimposed on a quasi-periodical data set. The procedure produces optimal values of crystallographic periods and orientations of the symmetry axes. This information is used for selecting coherent data sets within a crystallographic cluster. Superposition of cells from the same cluster and calculation of an average periodical structure improves the signal to noise ratio, which leads from nano to subnano resolution of the protein structure. The number of superimposed cells N defines the resolution gain factor N. In the case of hydrofobin, the value of N lies in the range of 25-100. This allows for the determination of fine structural details of HFBI. Average structures obtained from different domains of the protein layer also show a high degree of reproducibility.

This account highlights recent progress towards understanding the complex hierarchical levels of solid‐state structure in a prototypical helical hairy‐rod polyfluorene, poly[9,9‐bis(2‐ethylhexyl)fluorene‐2,7‐diyl] (or PF2/6). This branched‐side‐chain containing polyfluorene undergoes a systematic intermolecular self‐assembly and liquid‐crystalline phase behavior in combination with uniaxial and biaxial alignment. The latter processes yield full three‐dimensional orientation of the crystallites and polymer chains. Also reviewed are the impact of the molecular structure and phase behavior on surface morphology, anisotropic film formation, and, ultimately, the overall impact of these physical attributes on optical constants. This particular polyfluorene also represents a model system for demonstrating the applicability of mean‐field theory in detailing the self‐organization of aligned hairy‐rod block‐copolymer systems. These results of PF2/6 are compared to those of other archetypical π‐conjugated hairy‐rod polymers. General guidelines of how molecular weight influences nanostructure, phase behavior, alignment, and surface morphology are given.

The surface structure of uniaxially aligned poly(9,9‐bis(ethylhexyl)‐fluorene‐2,7‐diyl) films on rubbed polyimide has been studied as a function of molecular weight (Mn= 3–150 kg mol–1, number‐average molecular weight) using polarized microscopy, atomic force microscopy (AFM), X‐ray reflectivity, and grazing‐incidence X‐ray diffraction. At the threshold Mn, Mn* = 104g mol–1, there is a prominent transition in morphology from featureless (Mn< Mn*) to rough (Mn> Mn*), corresponding to the nematic–hexagonal phase transition. The hexagonal phase reveals two coexistent crystallite types in the whole film and at least one crystallite type has been observed at the surface by AFM. The combined optimization of alignment and surface smoothness is achieved slightly below Mn* while the combined optimization of orientational and local order and moderately smooth surface is achieved slightly above Mn*.

We report self-assembly and electronic conductivity transitions in polyaniline (PANI) where the iminic nitrogens are protonated by sulfonic acid-terminated low molecular weight poly(ethylene oxide) CH3−(O−C2H4−)46−CH2−SO3H (PEOSA), i.e., which contains 46 ethylene oxide repeat units. The complex PANI(PEOSA)0.5 self-assembles due to the comb-shaped architecture consisting of the PANI backbone and the supramolecular PEO side chains, as characterized using small- and wide-angle X-ray scattering (SAXS and WAXS) and transmission electron microscopy (TEM). PEO in the complex PANI(PEOSA)0.5 is crystalline near room temperature; TEM and SAXS indicate lamellar self-assembly with a long period of ca. 150 Å, and the conductivity is of the order 10^-4 S/cm. A collapse of the self-assembly periodicity to 115 Å is observed at ca. 55 °C during a slow heating at 1 °C/min, and the conductivity drops stepwise to ca. half of the value as the PEO chains melt. Even if the observed conductivity transition is still relatively small, it is reproducible and reversible upon heating and cooling, with some hysteresis. We expect that the concept can be developed to open new possibilities for responsive conjugated polymers.

We present a new technique for orienting polymer semiconductor thin films. In our technique, polymer chains are rigorously oriented without using any mechanical tools and with minimal risk of film contamination. The technique is based on the mechanical force resulting from the in‐plane shrinkage exerted by a shrinker (top layer) that is used to orient the semiconductor beneath an intermediate layer; the latter acting as a force mediator. The chain orientation is demonstrated by several techniques such as crossed‐polarizer microscopy, atomic force microscopy, grazing‐incidence X‐ray diffraction, and polarized absorption. The orientation geometry is controlled by the shrinking process and the shrinker area. The semiconductivity of the film only stems from the transistor device structures under study, and the method can therefore be generalized.

We report on the influence of the molecular weight (Mn) on the alignment and structure of poly(9,9-bis(ethylhexyl)fluorene-2,7-diyl) (PF2/6) in thin films on rubbed polyimide in the equilibrium. The degree of alignment has been studied using optical spectroscopy and compared to theoretical arguments. The structure of PF2/6 has been studied using grazing-incidence X-ray diffraction. PF2/6 realizes a threshold molecular weight Mn* = 10⁴ g/mol separating a low Mn (LMW, Mn &lt; Mn*) and a high Mn (HMW, Mn > Mn*) region. LMW materials show only the nematic (Nem) phase while HMW compounds show hexagonal (Hex) and Nem phases at low and high temperatures, respectively. LMW samples align equally well at any temperature above the glass transition, and the dichroic ratio, R, increases with Mn. HMW material aligns well in the Nem regime, and R drops exponentially with Mn, which is in agreement with the theory. The orientational order is maximized near Mn*, and the orientational order parameter is >0.9. HMW samples, whether aligned or not, reveal two kinds of coexistent Hex crystallites distributed in the sample plane having one crystal axis a perpendicular or parallel to the surface. Local order within the triaxially aligned Hex phase surpasses that of the in-plane aligned Hex phase.

Electrically conducting hexagonally self-assembled nanostructures of poly(aniline) (PANI) protonated with 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA) and hydrogen bonded with resorcinol (res), 4-ethylresorcinol (C2res) or 4-hexylresorcinol (C6res) are studied. Small-angle X-ray scattering (SAXS) of PANI(AMPSA)0.5(Cnres)y with y = 0, ..., 1.5 indicate cylindrical self-assembly in all cases, and the long period depends on n and y. Addition of Cnres leads to plasticization and an increase of conductivity of up to ca. 4 orders of magnitude until saturation is achieved upon approaching y = 1. Simultaneously, the temperature gradient of the conductivity dσ/dT near the room temperature changes from positive to negative, which is reminescent to a transition from a thermally activated hopping-type to a more “metallic-like” behavior. It is suggested that, upon complexation with especially res and C2res, the PANI chains become progressively more confined in cylinders suggesting their stretching. Overall alignment of the local self-assembled domains was also aimed. In films, anisotropic overall structure and conductivity are observed upon pressing the “melt” samples between two glass plates. In more bulky samples, so far, large amplitude oscillating shear flow leads to biaxial structural anisotropy without observable conductivity anisotropy, potentially indicating the importance of residual defects for the transport properties.

We report a novel structural hierarchy where a flow-aligned hexagonal self-organized structure is combined with a polyelectrolytic self-organization on a smaller length scale and where the two structures are mutually parallel. Polystyrene-block-poly(4-vinylpyridine) (PS-block-P4VP) is selected with a short P4VP block, which is protonated with p-toluenesulfonic acid (TSA) and further hydrogen bonded with 3-n-pentadecylphenol (PDP). To suppress the amount of free (uncomplexed) acid which we expected to have adverse effects during the extended shearing at the elevated temperatures, a safely less than stoichiometric amount of TSA was used, i.e., PS-block-P4VP(TSA)0.9(PDP)1.0. The formation of the supramolecules and the resulting structures were investigated using infrared spectroscopy (FTIR), small-angle X-ray scattering (SAXS), and transmission electron microscopy (TEM). As the weight fraction of P4VP(TSA)0.9(PDP)1.0 is ca. 20%, hexagonal self-organization occurs, as shown by SAXS. Shear flow leads to remarkably well-aligned structures. SAXS also indicates an internal structure within the P4VP(TSA)0.9(PDP)1.0 blocks with a long period of 41 Å. In contrast to the previously observed structural hierarchies in diblock copolymer/amphiphile supramolecules, which contained mutually perpendicular structures, e.g., lamellae within cylinders, in the present case SAXS in combination with models suggests internal polyelectrolytic layers parallel to the hexagonally ordered microphases. These aligned conducting nanochannels also manifest as a slight overall conductivity anisotropy.

We show a concept where coordination of amphiphiles to one block of a block copolymer leads to polymeric supramolecules and self-organization and that mesoporous materials can be achieved with a dense set of polymer brushes at the surfaces upon cleaving the amphiphiles by extraction with a selective solvent. Polystyrene-block-poly(4-vinylpyridine) (PS-block-P4VP) is used with zinc dodecylbenzenesulfonate (Zn(DBS)2) which can coordinate to the lone electron pairs of the pyridine nitrogens in the P4VP block, leading to complexes PS-block-P4VP[Zn(DBS)2]y. Coordination of Zn(DBS)2 and structure formation were investigated using Fourier transformation infrared spectroscopy (FTIR), small- and wide-angle X-ray scattering (SAXS and WAXS), and transmission electron microscopy (TEM). Lamellar structure was observed and even points toward a structural hierarchy for high molecular weight block copolymers. FTIR, SAXS, and TEM showed that most of Zn(DBS)2 can be extracted from such templates using methanol, leading to lamellar porous structures. P4VP brushes cover the resulting pore surfaces. The structures do not collapse probably due to the glassy PS and defects in the nonaligned structure. Compared to hydrogen bonding, coordination allows bonding of higher molecular weight amphiphiles due to the stronger attraction.

Wide and anomalous small-angle X-ray scattering (WAXS, ASAXS) methods were used to study the structure of the grafted polyethylene-based palladium catalysts and to find out how the grafting material, polystyrene, poly(acrylic acid), or poly(4-vinylpyridine), affects the structure of the catalyst. The Pd content of the samples was about 5% and Pd(II) was reduced to Pd(0) using the same reducing agent, HCHO. The starting polyethylene fiber was semicrystalline and this structure was not destroyed in the different preparation processes. Pd salts did not crystallize in the samples and the smallest Pd(II) particles were formed in the poly(4-vinylpyridine) grafted sample. Pd(0) crystallites with the average sizes of 35 and 60 Å were formed in the poly(acrylic acid)- and polystyrene-grafted samples, respectively, after reduction of Pd(II) to Pd(0). The poly(4-vinylpyridine)-grafted reduced sample did not contain Pd(0) crystallites. Pd(0) particles showed a tendency to be smaller than Pd(II) particles. The volume distribution of Pd(0) particles of the polystyrene-grafted sample was heterogeneous and indicated a large population of particles with the radii of 60−250 Å. For the poly(acrylic acid)-grafted sample the volume distribution was bimodal, containing maxima at 17 and 58 Å. The smallest Pd(0) particles were formed in the poly(4-vinyl pyridine)-grafted sample and the maxima of the distribution were at 9 and 20 Å.

We report self-organized polymer electrolytes based on poly(styrene)-block-poly(4-vinylpyridine) (PS-block-P4VP). Liquidlike ethylene oxide (EO) oligomers with sulfonic acid end groups are bonded to the P4VP block, leading to comb-shaped supramolecules with the PS-block-P4VP backbone. Lithium perchlorate (LiClO4) has been added to the EO-rich domains. Small- and wide-angle X-ray scattering in combination with Fourier transformation infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), ac impedance, and dynamic mechanical spectroscopy (DMA) suggests alternating lamellae of reinforcing glassy PS domains and ionically conducting “nanochannels” consisting of poly(4-vinylpyridinium), oligomeric ethylene oxide sulfonates, and LiClO4. The long period of the self-organization is ca. 300 Å. So far, the ionic conductivity levels remained relatively low, i.e., 10^-7−10^-6 S/cm at room temperature and 10^-5−10^-4 S/cm at 80 °C. However, as self-organization of polymeric supramolecules allows combining glassy reinforcing domains and well-plasticized domains consisting of oligomers with high segmental motions, there may exist possibilities to tune feasible combination of electrical and mechanical properties.

Seven different fluoropolymer films were used as matrix materials for radiation-grafted ion-exchange membranes. The crystallinity and preferred orientation of these membranes were studied with wide-angle X-ray scattering, and the lamellar structure of the membranes was examined with small-angle X-ray scattering. The crystallinity of poly(vinylidene fluoride) (PVDF)-based matrix materials varied between 57 and 40%, and the crystallinity of the sulfonated samples varied between 34 and 23%. The lamellar periods of PVDF-based matrix materials were about 115 Å, and the lamellar periods of poly(ethylene-alt-tetrafluoroethylene) and poly(tetrafluoroethylene-co-hexafluoropropylene) were 250 and 212 Å, respectively. When the samples were grafted, the lamellar periods increased. Correlation function analysis showed very clearly that the long-range order decreased because of grafting and sulfonation processes. For those samples that showed good proton conductivity, the lamellar period also increased because of sulfonation. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1539–1555, 2002

Seven different fluoropolymer films were used as matrix materials for radiation-grafted ion-exchange membranes. The crystallinity and preferred orientation of these membranes were studied with wide-angle X-ray scattering, and the lamellar structure of the membranes was examined with small-angle X-ray scattering. The crystallinity of poly(vinylidene fluoride) (PVDF)-based matrix materials varied between 57 and 40%, and the crystallinity of the sulfonated samples varied between 34 and 23%. The lamellar periods of PVDF-based matrix materials were about 115 Å, and the lamellar periods of poly(ethylene-alt-tetrafluoroethylene) and poly(tetrafluoroethylene-co-hexafluoropropylene) were 250 and 212 Å, respectively. When the samples were grafted, the lamellar periods increased. Correlation function analysis showed very clearly that the long-range order decreased because of grafting and sulfonation processes. For those samples that showed good proton conductivity, the lamellar period also increased because of sulfonation. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1539–1555, 2002

A concept is demonstrated for comb-shaped supramolecules based on dodecylbenzenesulfonic acid-doped polyaniline, i.e., PANI(DBSA)0.5, by complexation with zinc dodecylbenzenesulfonate, Zn(DBS)2. Model studies using related protonated single crystalline bipyridine oligomers suggest that Zn(DBS)2 molecules are bonded by Zn²⁺- and water-mediated hydrogen bonds to the sulfonates of PANI(DBSA)0.5. The comb-shaped supramolecules, denoted as PANI(DBSA)0.5[Zn(DBS)2]x with x = 0.25, 0.5, 0.75, 1.0, and 1.5, self-organize as lamellar structures due to the repulsion between the alkyl chains and the polar moieties leading to plasticized materials. So far, the conductivity levels are low, i.e., in the range 10^-7 S/cm, potentially requiring optimization of the lengths and the amounts of side groups. The concept allows generalization to complex functional groups along sulfonic acid protonated polyaniline chains.

The objective of this work was to use both X-ray and differential scanning calorimetry techniques in a comparative study of the lamellar and crystalline structures of heterogeneous and homogeneous ethylene-α-copolymers. The samples differed in the comonomer type (1-butene, 1-hexene, 1-octene, and hexadecene), comonomer content, and catalyst used in the polymerizations. Step crystallizations were performed with differential scanning calorimetry, and the crystallinity and lamellar thicknesses of the different crystal populations were determined. Wide-angle X-ray scattering was used to determine crystallinities, average sizes of the crystallites, and dimensions of the orthorhombic unit cell. The average thickness, separation of the lamellae, and volume fractions of the crystalline phase were determined by small-angle X-ray scattering (SAXS). The results revealed that at densities below 900 kg/m³, polymers were organized as poorly organized crystal bundles. The lamellar distances were smaller and the lamellar thickness distributions were narrower for the homogeneous ethylene copolymers than for the heterogeneous ones. Step-crystallization experiments by SAXS demonstrated that the long period increased after annealing. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1860–1875, 2001

A characteristic intermediate segregation type chain length dependence of the long period D of the lamellar microdomain structure of a class of comb−coil supramolecules is reported. The supramolecular comb−coil diblock copolymers studied consist of a polystyrene (PS) “coil” block and a “comb” block of poly(4-vinylpyridine) (P4VP) either hydrogen bonded to pentadecyl phenol (PDP) (i.e., P4VP(PDP)-b-PS) or first protonated with methanesulfonic acid (MSA) and then hydrogen bonded to PDP (i.e., P4VP(MSA)(PDP)-b-PS). In both cases we find a scaling D ~ %@mt;sys@%%@ital@%N%@rsf@%%@sx@%tot%@be@%δ%@sxx@%%@mx@% , δ ≅ 0.8, where Ntot denotes the total number of monomers of the P4VP-b-PS backbone. In the case of diblock copolymers this would correspond to a characteristic intermediate segregation regime behavior. Pure PS-b-P4VP, on the other hand, shows the expected strong segregation behavior D ~ %@mt;sys@%%@ital@%N%@rsf@%%@sx@%tot%@be@%δ%@sxx@%%@mx@% , δ ≅ 0.7.

The structure of lyotropic liquid crystalline or gellike phases formed in cationic starch (CS)/anionic surfactant/water systems in the temperature range 25−80 °C has been investigated by small-angle X-ray scattering. The surfactants were sodium dodecyl sulfate (SDS), sodium decanoate (NaDe), sodium dodecanoate (NaDod), sodium palmitate (NaPal), sodium oleate (NaOl), and sodium erucate (NaEr). The phases were in equilibrium with aqueous solutions at 60 °C and contained 15−25 wt % of CS and 10−30 wt % of surfactant, depending on the charge density of the CS and the chain length of the surfactant. The phases consist of CS/surfactant aggregates arranged in long-range structures similar to lyotropic mesophases formed by the pure surfactants alone, but they separate from aqueous solutions at much lower surfactant concentrations. When the charge density of the CS is low or the surfactant hydrocarbon chain is short, cubic or hexagonal phases are formed. As expected, the formation of lamellar phase is promoted by increasing these parameters. Temperature affects the stability of the phases and their structure. At high temperatures the long-range order breaks down, and the phases are akin to concentrated micellar CS/surfactant solutions.

We show that the emeraldine base form of polyaniline (PANI) forms self-organized (mesomorphic) structures upon mixing with an amphiphilic oligomer zinc dodecyl benzenesulfonate, Zn(DBS)2. The number of Zn(DBS)2 molecules vs the number of PhN repeat units of PANI was selected to be x = 0, 0.125, 0.25, 0.5, and 1.0, and the mixtures were denoted as PANI[Zn(DBS)2]x according to their nominal compositions. PANI consists of alternating quinone diimine and benzene diamine groups. FT-IR and UV−vis spectroscopies reveal changes in the quinone diimine moieties upon adding Zn(DBS)2, thus suggesting coordination to the iminic nitrogens to form comb-shaped supramolecules PANI[Zn(DBS)2]0.5. Their structure formation was studied using small-angle X-ray scattering and electron microscopy. The competition between the attraction (coordination) and repulsion (dodecyl tails) leads to a self-organized lamellar phase with a long period of ca. 31 Å. Further increase of Zn(DBS)2 did not reveal clear changes in FT-IR and UV−vis but results in plasticization to render viscous fluid upon heating for x = 1.0, in contrast to the uncomplexed PANI which is infusible.

Comb-shaped or hairy rodlike supramolecules can be obtained by hydrogen bonding rigid rod polymers and amphiphilic oligomers. Here we introduce a concept to achieve electrically conducting acid doped PANI to allow cylindrical self-organization. PANI is doped with camphorsulfonic acid (CSA) where 4-hexylresorcinol (Hres) is hydrogen bonded to form supramolecules, which further undergo self-organization. The structure formation of PANI(CSA)0.5(Hres)y complexes is discussed on the basis of small- and wide-angle X-ray scattering and electrical conductivity. Highly ordered hexagonal cylindrical structures were observed with a distance between the cylinders around 35 Å. Electrical conductivity increases 2 orders of magnitude upon formation of cylindrical structures, potentially due to confinement of PANI chains within the cylinders. The method would then allow an easy preparation of nanoscale organic conducting wires, just by mixing the components together.

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Supramolecular hierarchical conducting nanostructures are obtained by complexing amphiphilic oligomers with block copolymers. Nominally each pyridine group of poly(styrene)-block-poly(4-vinyl pyridine), i.e. (PS-block-P4VP), is first protonated by methane sulphonic acid (MSA) to yield PS-block-P4VP(MSA.)1.0. It is further hydrogen bonded with stoichiometric amount of pentadecyl phenol (PDP) to form PS-block-P4VP(MSA)1.0(PDP)1.0. The polyelectrolytic domains are subject to reversible phase transitions from ”semi Id” slabs to 2d lamellae and further to 1d cylinders upon heating. The transitions manifest in the thermally activated conductivity. Extension to conjugated polymers is discussed to achieve temperature controlled switching based on electronic conductivity.

We show that polymeric materials characterized by two length scales are obtained if diblock copolymers are mixed with amphiphilic selective solvents, leading to self-organization which combines the “block copolymer length scale” with a much shorter “nanoscale”. In this work, the amphiphilic compound is 3-n-pentadecylphenol (PDP) which is hydrogen-bonded to the pyridine group of polystyrene-block-poly(4-vinylpyridine), i.e., PS-b-P4VP. The molecular architecture resembles comb-coil diblock copolymers A-block-(B-graft-C) but is obtained using the supramolecular assembly route. The structures were determined with a combination of transmission electron microscopy and small-angle X-ray scattering. On the block copolymer scale (300 Å range), the PS blocks are microphase-separated from the P4VP(PDP)x blocks, where x denotes the ratio between the number of phenol and pyridine groups. For PS-b-P4VP block copolymers having a spherical morphology and P4VP as the minority component, the structure of PS-b-P4VP(PDP)x changes from spherical to hexagonal and further to lamellar as a function of the amount of PDP added. For all comb-coil diblock copolymer morphologies, the P4VP(PDP)x domains are further “nanophase-separated” into lamellar structures due to microphase separation of the comb copolymer-like complex between P4VP and PDP. The morphology diagram is presented for stoichiometric conditions (x = 1), using a range of different PS-b-P4VP block copolymers.

The solid state of comb copolymer-like systems obtained by blending poly(4-vinylpyridine) with pentadecylphenol was studied by a combination of techniques. Depending on the amount of pentadecylphenol, several regimes are present. For 0.5 ≤ x ≤ 1.0 (x is the ratio between the number of phenol and pyridine groups) the alkyl tails form an interdigitated hexagonally packed crystalline layer. Small-angle X-ray scattering measurements show that for x = 1.5 and 2.0 the excess pentadecylphenol cocrystallizes with the associated pentadecylphenol, with the free phenol groups probably aggregating near the middle of the crystalline layer. For x ≥ 2.0 the orthorhombic crystal modification also appears. Finally for x ≥ 3.0, part of the excess pentadecylphenol macrophase separates on crystallization, forming an additional phase of pure pentadecylphenol with the familiar orthorhombic packing. These findings are similar to results obtained for real comb copolymer systems, i.e., containing covalently bonded side chains. However, our systems are essentially different due to the dynamic hydrogen-bonding equilibrium, which implies that the equilibrium solid state may always involve some form of macrophase separation.

Supramolecular hierarchical conducting nanostructures are obtained by complexing amphiphilic oligomers with block copolymers. Nominally each pyridine group of poly(styrene)-block-poly(4-vinyl pyridine), i.e. (PS-block-P4VP), is first protonated by methane sulphonic acid (MSA) to yield PS-block-P4VP(MSA.)1.0. It is further hydrogen bonded with stoichiometric amount of pentadecyl phenol (PDP) to form PS-block-P4VP(MSA)1.0(PDP)1.0. The polyelectrolytic domains are subject to reversible phase transitions from ”semi Id” slabs to 2d lamellae and further to 1d cylinders upon heating. The transitions manifest in the thermally activated conductivity. Extension to conjugated polymers is discussed to achieve temperature controlled switching based on electronic conductivity.

Dynamic mechanical spectroscopy (DMS) is used to further investigate the recently observed order−disorder transition (ODT) in comblike block copolymers obtained by hydrogen bonding between poly(4-vinylpyridine) and pentadecylphenol (P4VP−PDPx). For stoichiometric amounts of pyridine and phenol, i.e., x = 1.0, the ODT to a lamellar structure occurs at T ≃ 65 °C. The dynamic moduli G‘ and G‘‘ simultaneously show a crossover from a liquidlike behavior (G‘ ~ ω^1.5 and G‘‘ ~ ω) to a response intermediate between a Newtonian fluid and a solid (G‘ ≈ G‘‘ ~ ω^1/2). The behavior above TODT differs slightly from a homopolymer melt (G‘ ~ ω^2.0) due to composition fluctuations, whereas the behavior below TODT is characteristic for quenched block copolymer lamellar phases with local uniaxial order and global isotropy. Near room temperature, a transition to solid behavior (G ~ ω⁰) takes place due to crystallization of the alkyl side chains. Larger amounts of PDP lower the TODT temperature, and for x = 2.0 the transition to solid response occurs directly from the disordered state. Small and wide angle X-ray scattering (SAXS and WAXS) experiments and differential scanning calorimetry (DSC) corroborate these findings. Furthermore, SAXS and WAXS demonstrate that the low-temperature state of P4VP−PDP2.0 is not stable and indicate that ultimately macrophase separation into a pure crystalline PDP phase and a microphase separated P4VP−PDP phase occurs.

Properly selected hydrogen bonding suffices to induce mesomorphic structures in mixtures of flexible polymers and nonmesogenic surfactants. For poly(4-vinylpyridine)−3-pentadecylphenol (P4VP(PDP)x) complexes, the long period of the lamellar structure decreases as x^-1 (x is the number of PDP molecules per P4VP repeat unit) in complete contrast to similar polyelectrolyte systems. Upon cooling from 80 °C to the room temperature, the long period gradually increases and levels off at around 30 °C at a value which is approximately 4 Å above the starting value. After an induction time, a structural transformation occurs in the highly complexed samples, due to the crystallization of the alkyl side chains. It is accompanied by a sudden decrease in the long period of approximately 5 Å. However, the structure is not stable and after an additional induction time both structures are present in the samples. Arguments to explain most of the observed phenomena will be given.

The critical interaction strength to induce mesomorphic structures in flexible polymers by complexing with surfactants is determined by using surfactants with different hydrogen-bonding strengths. Two essential requirements have to be satisfied:  (i) the association has to be strong enough, otherwise the structure dissociates. (ii) The polar−nonpolar repulsion has to be sufficiently strong to induce microphase separation. If the latter requirement is not satisfied, but the association is sufficiently strong, a characteristic comb polymer-like SAXS peak will still be present in the homogeneous melt state. To address these issues experimentally, poly(4-vinylpyridine) (P4VP) was combined with different classes of hydrogen-bonding surfactants:  alkyl aromatic alcohols, alkyl carboxylic acids, alkyl aliphatic alcohols, and alkyl aliphatic amines. FTIR, SAXS, WAXS, and optical microscopy demonstrate that alkyl aromatic alcohols, such as 1-dodecyl 3,4,5-trihydroxybenzoate yield mesomorphic structures at not too high a temperature. Alkyl carboxylic acids are somewhat less effective. In the melt state, the SAXS data still show a peak, but because no birefringence could be found, the peak is attributed to block copolymer-like concentration fluctuations in an otherwise homogeneous state. Aliphatic alkyl alcohols yield still weaker hydrogen bonding. In the melt the short alkyl aliphatic alcohol surfactants form a homogeneous mixture with P4VP, but a SAXS peak is no longer observed. The longer ones macrophase separate. Both the alkyl carboxylic acids and the short alkyl aliphatic alcohols partly macrophase separate at lower temperatures due to crystallization.

We report here on the extension to elastomers of the idea of inducing nanoscale ordering in supramolecular polymer systems based on the principle of hydrogen bonding between amphiphiles and (block co-)polymers. Three different networks have been synthesized using 4-vinylpyridine and divinylbenzene (0.5, 1.0, and 2.0 mol %, respectively) and are further complexed with pentadecylphenol or nonadecylphenol. For low degrees of cross-linking (0.5 and 1.0 mol % divinylbenzene), mesomorphic structures are formed, and order−disorder transitions are observed by small-angle X-ray scattering (SAXS) and differential scanning calorimetry. For the highest degree of cross-linking (2.0 mol % divinylbenzene), mesomorphic structures is no longer observed. The presence of ordered lamellar structures is confirmed by transmission electron microscopy (TEM). SAXS and TEM clearly reveal the deteriorating effect of an increasing degree of cross-linking on the structure formation.

We demonstrate thermoreversible gelation of a conductive polymer, i.e., rubber-like melt processible electrically conducting compounds. Combination of viscoelastic and electrical conductivity measurements suggests network formation in the gel state and gel melting at elevated temperatures. The gels have been prepared by dissolving polyaniline in dodecylbenzenesulfonic acid (DBSA) using formic acid as a processing medium which was removed at the end. Importantly, without formic acid, reversible gelation and particle-free materials were not achieved even at the resolution of optical microscopy. For T &lt; Tgel the materials behave elastically in compression experiments, the storage and loss moduli do not depend much on frequency, and the electrical conductivity is primarily electronic, probably due to high chain-to-chain hopping conductivity. For T > Tgel the onset of liquid-like flow is detected using modified ball drop method by dynamic mechanical analysis, the dynamic moduli become strongly frequency dependent, and the electrical conductivity drops orders of magnitude to the value corresponding to the ionic conductivity of DBSA, suggesting that the chains are not in direct contact. The physical cross-links are probably localized mesomorphic domains which allow melting.

A new technique for orienting thin polymer semiconductor films is reported by Österbacka and co‐workers on p. 1095. The technique uses the mechanical force of a shrinking polymer transferred through a polymer multilayer structure. The orientation is obtained using three polymer layers, where the uppermost layer shrinks resulting in orientation of the semiconductor film beneath the intermediate layer. The topmost and intermediate polymer films are removed to reveal the oriented surface. The cover shows a crossed‐polarizer microscopy image of an oriented regio‐regular poly(3‐hexylthiophene) film.