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A new family of polymer electrolytes based on a poly(allyl glycidyl ether) (PAGE) platform has been developed that overcomes many of the limitations of poly(ethylene oxide) (PEO) for battery electrolyte applications. PAGE was shown to have peak conductivities at [O]/[Li] = 16, with σ > 3 × 10–5S/cm at 25 °C and σ > 5 × 10–4S/cm at 80 °C. Below 60 °C, PAGE has a conductivity that is 10–100 times higher than that of PEO at equivalent salt concentrations with this disparity in conductivities between PAGE and PEO increasing with decreasing temperature. In addition, the synthetic versatility of allyl glycidyl ether as a building block is demonstrated by the preparation and evaluation of various AGE–EO macromolecular architectures that show superior performance to both PAGE and PEO.

We investigate the effect of surface energy and chain architecture on the orientation of microdomains in relatively thick films (600-800 nm) of lamellar and cylindrical block copolymers of poly(cyclohexylethylene) (C) and poly(ethylene) (E). The E block has 26 ethyl branches per 1000 backbone carbon atoms. Melt surface energies of the C and E blocks are 22.3 and 20.9 mJ/m2, respectively. Grazing-incidence small-angle X-ray scattering (GISAXS), scanning force microscopy (SFM), and cross-sectional transmission electron microscopy (TEM) show that cylindrical and lamellar CEC triblock copolymers orient their microdomains normal to the surface throughout the film thickness. However, a lamellar CE diblock copolymer prefers a parallel orientation of the lamellae relative to the surface with an E surface layer. Moreover, a cylindrical CEBC triblock copolymer where the EB block has 125 ethyl branches per 1000 backbone carbon atoms leads to EB cylinder domains that always orient parallel to the surface. In this case the lower surface energy EB block dominates the surface. Calculations using self-consistent-field theory allow us to interpret the experimental results in terms of the entropic cost of forming a wetting layer comprised entirely of looping blocks. Thus, in triblock copolymers, parallel orientations are only stabilized when the midblock has the lower surface energy, and the difference in surface energies of the two blocks is large enough to compensate for this conformational penalty, which is absent in diblock copolymers.

We investigate the influence of chain architecture and microdomain orientation on the deformation and fracture properties of relatively thick films (600−800 nm) of poly(cyclohexylethylene)−poly(ethylene) (PCHE−PE) block copolymers with various architectures. Optical microscopy, transmission electron microscopy, and scanning force microscopy are used to study the domain structure as well as examine the details of deformation and fracture of films stretched on ductile copper grids. For lamellar block copolymers the deformation and fracture properties depend significantly on the chain architecture. Annealed diblock copolymer films containing 48% PE show 100% failure at very low strains of 5% with a median strain to failure of 2%, whereas the lamellar triblock (CEC) and pentablock copolymer (CECEC) films do not fail at strains up to 27%. However, a 50/50 blend of diblock (CE MW 22 kg/mol, fPE 0.48) and triblock (CEC MW 45 kg/mol, fPE 0.48) copolymers shows a median strain to failure of about 6.4%. A 50/50 blend of the same diblock and pentablock (CECEC MW 66 kg/mol, fPE 0.48) copolymers, on the other hand, does not show any failure at strains up to 27%. Experiments on a cylinder-forming pentablock copolymer (CECEC MW 60 kg/mol, fPE 0.25) with slow ordering kinetics show that the maximum ductility with no failure at the maximum strain of 27% is obtained if the PE cylinders are randomly oriented (spun-cast films). Films having cylinders that are aligned parallel as well as perpendicular to the tensile direction (annealed for 3 days with cylinders lying down in the plane of the film) show a reduction in ductility with 30% failure at the maximum strain. As the proportion of cylinders aligned perpendicular to the tensile direction is increased (by increasing the annealing time to 7 days, the top half of the film shows cylinders that align normal to the film plane), 100% of the film squares fail at the maximum strain of 27% with a median strain to failure of about 19%. Moreover, in a film half as thick (∼300 nm), after a 7 day anneal, the perpendicular orientation persists throughout the film thickness. This sample shows complete failure at about 22% strain with a median strain to failure of about 15.7%. These results indicate that the orientation of the cylinders in the films has a strong effect on the mechanical properties of this pentablock copolymer, similar to conclusions reached previously for the triblock copolymer architecture. The results obtained in these studies are compared with those reported in previous works for the same system to ascertain the relative effect of chain architecture, microdomain orientation, and composition on the mechanical behavior of the block copolymer thin films.

A strategy for controlling the location of gold nanoparticles within block copolymer domains through varying the surface coverage of gold nanoparticles by end-attached polymer ligands is described. Gold nanoparticles coated by short thiol end functional polystyrene homopolymers (PS-SH) (Mn 3.4 kg/mol) are incorporated into a poly(styrene-b-2-vinylpyridine) diblock copolymer template (PS-b-P2VP) (Mn 196 kg/mol), the P2VP block of which has a more favorable interaction with a bare gold particle surface than does the PS block. The areal chain density of the PS-SH ligands on gold particles is varied by changing the mole ratio of PS-SH chains to gold atoms. It is found that the areal density of PS chains on the gold particles is critical to controlling their location in block copolymer templates. PS-coated gold nanoparticles with PS chain areal density higher than 1.6 chains/nm2are dispersed in PS domains of PS-b-P2VP while they are segregated along the interface between PS and P2VP domains of PS-b-P2VP for PS chain areal density <1.3 chains/nm2. Even at extremely low grafting densities of polymer ligands, gold nanoparticles can be stabilized in solution, and self-assembly of these nanoparticles can be controlled within the block copolymer template.

We report the synthesis of tapered block copolymers of ethylene with 5-norbornen-2-yl acetate (1) by the nickel catalyst system [N-(2,6-diisopropylphenyl)-2-(2,6-diisopropylphenylimino)propanamide] Ni(η1-CH2Ph)(PMe3) (2) and Ni(COD)2 (bis(1,4-cyclooctadiene)nickel). This technique utilizes a one-pot semibatch copolymerization in which ethylene is continuously added while 1 is depleted by incorporation into the polymer chain. The simplicity of this technique allows the construction of a polymer library, which enabled us to study the effect of polymer composition and chain length on solid-state morphology and mechanical and thermal properties. From these studies we were able to derive a profile relating the probability of 1 insertion vs degree of polymerization (Xn). Under proper experimental conditions, these tapered polymers form ordered microphase-separated morphologies where the phase morphology is modulated by the polymer chain length. The percent crystallinity and storage modulus of the polymers were found to be chain length dependent.

The temperature-dependent alignment of semiconducting liquid crystalline fluorene−thiophene copolymer (F8T2) thin film surfaces was investigated using the near-edge X-ray absorption fine structure (NEXAFS) technique. Partial electron yield spectra were recorded over a range of temperatures in order to observe directly the surface orientation as the polymer is heated and cooled through glass, crystal, and liquid crystal phases. In addition, samples annealed under varying processing conditions and quenched to room temperature were analyzed. The NEXAFS data show that (a) in thin F8T2 films at all temperatures the polymer backbone lies in the plane of the substrate, (b) the fluorene and thiophene rings are rotated randomly about the molecular axis, (c) orientation of the polymer backbone can be controlled using a rubbed polyimide alignment layer as a template for liquid crystal orientation, and (d) under proper annealing conditions there is strong temperature-dependent alignment of the copolymer main-chain axis to the rubbing direction which extends from the polyimide/F8T2 interface all the way to the F8T2 surface. The surface alignment does not disappear after annealing at temperatures ∼30 K above the bulk nematic to isotropic transition.

The edges of channels etched into topographically patterned substrates impart orientational order to monolayers of poly(styrene-b-2-vinylpyridine) cylinders. Quantitative measures of orientational order as well as defect densities are presented for cylinder arrays confined in channels of width varying between 1 and 3 μm, with little, if any, difference observed between these different channel widths. As the temperature is raised, the cylinder monolayers undergo a nematic-to-isotropic disordering transition. However, above this transition temperature, orientational order is retained within several cylinder repeat spacings next to the channel edges (distances significantly less than the channel widths considered here). This effect arises from an effective repulsion of defects from those edges, as confirmed by position-dependent defect density measurements.

A new combination of polymer chains and small colloids is presented in order to investigate the behavior of colloid−polymer mixtures in solution (CP) in the protein limit. To this end, hydroxy-functionalized silica particles (OHSil) were prepared according to a procedure [J. Am. Chem. Soc. 2003, 125, 3712], which led to colloid radii as small as 1.2 nm. Compared to this small size, the coil dimensions of the polystyrene (PS) chains used as the polymer component were larger by more than an order of magnitude. Investigation of the CP focused on the dimension of the PS chains in the presence of a varying amount of OHSil colloids. Chain size and shape were characterized by means of light scattering, viscosity experiments, and small-angle neutron scattering (SANS). Two solvents have been used. A mixture of dimethylformamide (DMF) with toluene was isorefractive to the OHSil particles, giving access to single chain behavior of PS. Pure DMF, on the other hand, allowed an efficient contrast matching of OHSil suitable for SANS experiments on fully deuterated PS. All characterization techniques provided clear evidence for a shrinking of the coil dimensions with increasing OHSil content in the solution. Particle scattering factors from SANS yielded a detailed picture of this chain compaction. The smallest coil dimensions were recorded close to the liquid−liquid phase boundary, occurring at an OHSil volume fraction of ~0.17. This is considered to be a first experimental evidence for a shift of the liquid−liquid phase boundary toward lower colloid volume fractions if the colloid size increases. Altogether, present data extend earlier measurements on two chemically different CP in the protein limit, thus establishing the observed shrinking to be a universally valid feature of these systems. The results are in qualitative agreement with theoretical predictions.

Alkoxyamines and persistent nitroxyl radicals are important regulators of nitroxide mediated radical polymerization (NMP). Because polymerization times decrease with increasing rate constant of the homolysis of the C−ON bond between the polymer chain and the nitroxyl moiety, the factors influencing the cleavage rate constant are of considerable interest. Here, we present the measurements of the rate constants (kd) of the C−ON bond cleavage in new cyclic alkoxyamine models. The homolysis rate constants of 9 new alkoxyamines and 33 others given by the literature are analyzed with regards to the contributions of the polar inductive/field (σI) effect, the steric (Es) effect and the intramolecular hydrogen bonding (IHB) effect of the nitroxyl moieties, using the multiparameter equation established by Marque, i.e., log(kd/kd,0) = −3.07σI − 0.88Es − 5.88. Cyclic steric constants r(Ri) for seven- and eight-membered rings are developed. Analysis of the results provides new insight on the importance of the conformation of the alkoxyamine on the values of kd.

Hyperbranched poly(ethylenimine) (PEI) with amino groups or carbohydrate terminal groups have been used as support materials for metal nanoparticles (i.e., Cu, Ag, Au, and Pt) in water. Various parameters have been optimized, such as pH, concentration of the polymer in solution, and [metal ions]/[polymer] ratio in order to obtain stable metal nanoparticles with a narrow size distribution. TEM measurements revealed that particles with a diameter as low as 1.4 nm were obtained. An increase of stability was obtained after functionalization of PEI with glycidol, gluconolactone, or lactobionic acid. In the case of Pt the catalytical activity of the corresponding nanoparticles was evidenced.

Mesostructured silica films were formed from cross-linked poly(d8-styrene-block-2-vinylpyridine) (dPS-b-P2VP) diblock copolymer template films by swelling with silica precursor solutions. The mesoscopic and macroscopic morphologies of the resulting materials depended strongly on the extent of P2VP cross-linking. Without cross-linking, extensive rearrangement of the initial 2D hexagonal arrangement of dPS cylinders took place during swelling, leading to wormlike mesostructures. At low extents of template cross-linking, osmotic stresses led to a surface-wrinkling instability with a morphology directed by the anisotropic mechanical properties of the swelled block copolymer mesostructure. At higher degrees of P2VP cross-linking, wrinkling was suppressed, and the composite silica/polymer mesostructures corresponded to essentially affine expansions of the initial template structures normal to the film plane. At low extents of P2VP cross-linking, the mesostructures of the hybrid block copolymer/silica films were preserved during oxidation and removal of the block copolymer template species, leading to stable mesoporous silica films. At high extents of P2VP cross-linking, however, insufficient amounts of silica were incorporated to form stable porous inorganic materials, leading to mesostructural collapse. An intermediate level of cross-linking allowed the preparation of stable mesoporous silica films with structures that closely resembled those of the initial template films.

We demonstrate that an analytical model can be used to interpret moiré patterns in scanning force microscopy images of spherical domain block copolymer films, yielding grain orientations and a more than 10-fold increase in scan size without requiring a tedious empirical calibration. Moiré patterns are the product of interference between two overlapping regular gratings and are sensitive to the grating periodicity and alignment. We apply this technique to SFM of a monolayer of a spherical domain block copolymer, where the SFM scan lines act as a reference grating, and the close-packed rows of the block copolymer domains form the sample grating. The block copolymer grain orientation and size are calculated from the moiré patterns using an analytical model. The accuracy of the model is confirmed by directly imaging the block copolymer lattice with high-resolution SFM. Furthermore, we investigate the moiré patterns of defects in this two-dimensional array of domains and demonstrate that dislocations can be reliably imaged depending on the pitch of the moiré fringes and the orientation of the Burgers vector of the dislocations.

Monolayer arrays of polystyrene−poly(2-vinylpyridine) diblock copolymer cylinders with excellent orientational order and a very low density of dislocations are prepared by cooling slowly from above the bulk order−disorder temperature (ODT) ~212 °C within silicon oxide channels one cylinder spacing a in depth and 2 μm in width. The translational order of this array, however, is short range with a correlation length of ~12a. If such an array is heated to a temperature above the glass transition temperature of the block copolymer (100 °C) but well below the ODT, a finite density of thermally generated dislocations is observed, which leads to a decrease in the translational correlation length and an appearance of quasi-long-range orientational order such that the orientational correlation function g2(r) decays as a power law, i.e., g2(r) ≈ (r/a)^-η2^(T). The state of disorder at any given temperature appears to be an equilibrium one since cylinder arrays with similar dislocation densities and correlation functions can be obtained either by heating from the well-ordered state or by cooling slowly directly to the final temperature and holding at that temperature for a sufficient time. Above a temperature of 195 °C, the orientational order becomes short range (g2(r) decaying exponentially with r), and a large density of disclinations is observed in addition to the dislocations. The cylinder array becomes isotropic above this temperature, which is ~20 °C below the bulk ODT. These results are in qualitative agreement with the theory of Toner and Nelson¹ which describes the thermal generation of disorder and ultimate melting of a two-dimensional smectic.