A polyethylene-like polymer with an in-chain vitamin C group was synthesized by olefin metathesis polymerization. Here, we describe both the synthesis and a comprehensive physical characterization. Because of the olefin metathesis synthesis, the vitamin C groups are equidistantly arranged in the polyethylene (PE) main chain. Their separation was adjusted to 20 CH2 units. After hydrogenation, a semicrystalline polymer is obtained that is soluble in polar solvents. Because of its size and steric effect, the vitamin C acts as a chain defect, which is expelled from the crystal lattice, yielding a lamellar crystal with a homogeneous thickness corresponding to the interdefect distance. The physical properties were examined by various methods including differential scanning calorimetry, X-ray scattering, and transmission electron microscopy. We show that vitamin C retains its radical scavenger properties despite being incorporated into a polyethylene chain. Furthermore, we demonstrate that it is degrading in alkaline conditions. To complete its suitability as a biocompatible material, cytotoxicity and cell uptake experiments were performed. We show that the polymer is nontoxic and that it is taken up in nanoparticular form via endocytosis processes into the cytoplasm of cells.

The molecular-scale structure and dynamics of confined liquids has increasingly gained relevance for applications in nanotechnology. Thus, a detailed knowledge of the structure of confined liquids on molecular length scales is of great interest for fundamental and applied sciences. To study confined structures under dynamic conditions, we constructed an in situ X-ray surface forces apparatus (X-SFA). This novel device can create a precisely controlled slit-pore confinement down to dimensions on the 10 nm scale by using a cylinder-on-flat geometry for the first time. Complementary structural information can be obtained by simultaneous force measurements and X-ray scattering experiments. The in-plane structure of liquids parallel to the slit pore and density profiles perpendicular to the confining interfaces are studied by X-ray scattering and reflectivity. The normal load between the opposing interfaces can be modulated to study the structural dynamics of confined liquids. The confinement gap distance is tracked simultaneously with nanometer precision by analyzing optical interference fringes of equal chromatic order. Relaxation processes can be studied by driving the system out of equilibrium by shear stress or compression/decompression cycles of the slit pore. The capability of the new device is demonstrated on the liquid crystal 4'-octyl-4-cyano-biphenyl (8CB) in its smectic A (SmA) mesophase. Its molecular-scale structure and orientation confined in 100 nm to 1.7 μm slit pores was studied under static and dynamic nonequilibrium conditions.

Correction for 'Surface induced smectic order in ionic liquids - an X-ray reflectivity study of [C22C1im]+[NTf2]-' by Julian Mars et al., Phys. Chem. Chem. Phys., 2017, 19, 26651-26661.

A common feature of ionic liquids composed of cations with long aliphatic side chains is structural heterogeneities on the nanometer length scale. This so-called microphase separation arises from the clustering of aliphatic moieties. The temperature dependence of the liquid bulk structure was studied by small-angle X-ray and neutron scattering for a set of methylimidazolium ([C18C1im]+, [C22C1im]+) based ionic liquids with tris(pentafluoroethyl)trifluorophosphate ([FAP]-), bis(trifluoromethylsulfonyl)imide ([NTf2]-), and bis(nonafluorobutylsulfonyl)imide ([NNf2]-) anions. The experimental data is quantitatively analyzed using a generalized Teubner-Strey model. Discussion of the resulting periodicity d and correlation length ξ shows that the structural heterogeneities are governed by the interplay between the alkyl chain length, the geometry of the anion, and entropic effects. Connections between the mesoscopic correlation functions, density, and entropy of fusion are discussed in comparison to alcohols. The observed dependencies allow predictions on the mesoscopic correlation functions based on macroscopic bulk quantities.

Tumor necrosis factor‐alpha (TNF‐α) is a pleiotropic immune stimulatory cytokine and natural endotoxin that can induce necrosis and regression in solid tumors. However, systemic administration of TNF‐α is not feasible due to its short half‐life and acute toxicity, preventing its widespread use in cancer treatment. Dendritic mesoporous silica nanoparticles (DMSN) are used coated with a pH‐responsive block copolymer gate system combining charged hyperbranched polyethylenimine and nonionic hydrophilic polyethylenglycol to encapsulate TNF‐α and deliver it into various cancer cell lines and dendritic cells. Half‐maximal effective concentration (EC 50 ) for loaded TNF‐α is reduced by more than two orders of magnitude. Particle stability and premature cargo release are assessed with enzyme‐linked immunosorbent assay. TNF‐α‐loaded particles are stable for up to 5 d in medium. Tumor cells are grown in vitro as 3D fluorescent ubiquitination‐based cell cycle indicator spheroids that mimic in vivo tumor architecture and microenvironment, allowing real‐time cell cycle imaging. DMSN penetrate these spheroids, release TNF‐α from its pores, preferentially affect cells in S/G2/M phase, and induce cell death in a time‐ and dose‐dependent manner. In conclusion, DMSN encapsulation is demonstrated, which is a promising approach to enhance delivery and efficacy of antitumor drugs, while minimizing adverse side effects.

Eight series of poly(alkyl methacrylate)s bearing different side chains and one series of poly(methyl acrylate) were randomly labeled with pyrene, and their ability to form pyrene excimer was characterized quantitatively by steady-state and time-resolved fluorescence to demonstrate that such measurements provide a quantitative measure of polymer chain dynamics (PCD) in solution. Each series of pyrene-labeled polymer showed increased excimer formation with increasing pyrene content, but the increase was more pronounced for the polymers known to be more flexible based on their reported glass transition temperature (T-g). In the case of the poly(alkyl methacrylate)s with a linear side chain, a shorter side chain resulted in increased excimer formation. Replacing a linear side chain with a more rigid one containing the same number of carbon atoms resulted in decreased mobility of the polymer. Fluorescence Blob Model (FBM) analysis of the fluorescence decays provided a more accurate representation Of those pyrenes that formed excimer by diffusion and thus reflected PCD more precisely. Global FBM analysis of the pyrene monomer and excimer fluorescence decays yielded the blob size N-blob and the product k(blob) X N-blob which reflects PCD. For each series, both N-blob and k(blob), X N-blob remained constant with pyrene content. Their average value < N-blob > and < k(blob) X N-blob > decreased substantially with increasing side-chain length, addition of the alpha-methyl substituent to poly(methyl acrylate) to yield poly(methyl methacrylate), or increased rigidity of the side chain, demonstrating that an increase in bulkiness or stiffening of the side- or main chain is associated with a pronounced decrease in chain mobility. These experiments are the first to demonstrate that pyrene excimer formation can be used to characterize quantitatively PCD in solution in the same manner that T-g is being used to characterize PCD in the bulk.