Investigation of the Nanoscale Morphology in Industrially Relevant Clearcoats of Waterborne Polymer Colloids by Means of Variable-Angle-Grazing Incidence Small-Angle X-ray Scattering

Soft polymer colloidal water suspensions are extremely important formulations for industrial applications such as water-based environmental-friendly coatings, paints, and adhesives. Homogeneity of the final coating at the micrometer and nanoscale is a crucial factor for optimal coating performance, such as barrier properties against solvent permeation. Here, we investigated the remnant nanostructure in slot-die-coated micrometer-sized thick clear coating films (clearcoats) of three different waterborne polymer colloids (pure soft, pure hard, and soft/hard multiphase), commonly utilized as primers in paint formulations [Mader et al. Prog. Org. Coat. 2011, 71, 123-135], using variable-angle grazing incidence small-angle X-ray scattering (GISAXS) complemented with cross-sectional atomic force microscopy (cs-AFM). After complete macroscopic drying, the coating films exhibit the presence of residual nanostructure with characteristic distance (d*) smaller than the original particle size and even smaller

Mechanochromic and thermochromic sensors based on graphene infused polymer opals

High quality opal‐like photonic crystals containing graphene are fabricated using evaporation‐driven self‐assembly of soft polymer colloids. A miniscule amount of pristine graphene within a colloidal crystal lattice results in the formation of colloidal crystals with a strong angle‐dependent structural color and a stop band that can be reversibly shifted across the visible spectrum. The crystals can be mechanically deformed or can reversibly change color as a function of their temperature, hence their sensitive mechanochromic and thermochromic response make them attractive candidates for a wide range of visual sensing applications. In particular, it is shown that the crystals are excellent candidates for visual strain sensors or integrated time‐temperature indicators which act over large temperature windows. Given the versatility of these crystals, this method represents a simple, inexpensive, and scalable approach to produce multifunctional graphene infused synthetic opals and opens up exciting applications for novel solution‐processable nanomaterial based photonics

In vivo comparison of arterial lumen dimensions assessed by co-registered three-dimensional (3D) quantitative coronary angiography, intravascular ultrasound and optical coherence tomography

This study sought to compare lumen dimensions as assessed by 3D quantitative coronary angiography (QCA) and by intravascular ultrasound (IVUS) or optical coherence tomography (OCT), and to assess the association of the discrepancy with vessel curvature. Coronary lumen dimensions often show discrepancies when assessed by X-ray angiography and by IVUS or OCT. One source of error concerns a possible mismatch in the selection of corresponding regions for the comparison. Therefore, we developed a novel, real-time co-registration approach to guarantee the point-to-point correspondence between the X-ray, IVUS and OCT images. A total of 74 patients with indication for cardiac catheterization were retrospectively included. Lumen morphometry was performed by 3D QCA and IVUS or OCT. For quantitative analysis, a novel, dedicated approach for co-registration and lumen detection was employed allowing for assessment of lumen size at multiple positions along the vessel. Vessel curvature was automatically calculated from the 3D arterial vessel centerline. Comparison of 3D QCA and IVUS was performed in 519 distinct positions in 40 vessels. Correlations were r = 0.761, r = 0.790, and r = 0.799 for short diameter (SD), long diameter (LD), and area, respectively. Lumen sizes were larger by IVUS (P < 0.001): SD, 2.51 ± 0.58 mm versus 2.34 ± 0.56 mm; LD, 3.02 ± 0.62 mm versus 2.63 ± 0.58 mm; Area, 6.29 ± 2.77 mm2versus 5.08 ± 2.34 mm2. Comparison of 3D QCA and OCT was performed in 541 distinct positions in 40 vessels. Correlations were r = 0.880, r = 0.881, and r = 0.897 for SD, LD, and area, respectively. Lumen sizes were larger by OCT (P < 0.001): SD, 2.70 ± 0.65 mm versus 2.57 ± 0.61 mm; LD, 3.11 ± 0.72 mm versus 2.80 ± 0.62 mm; Area 7.01 ± 3.28 mm2versus 5.93 ± 2.66 mm2. The vessel-based discrepancy between 3D QCA and IVUS or OCT long diameters increased with increasing vessel curvature. In conclusion, our comparison of co-registered 3D QCA and invasive imaging data suggests a bias towards larger lume

Complexation of halide anions and tricarboxylate anions by neutral urea-derivatized p-tert-butylcalix[6]arenes

Two neutral receptors for halide anions and tricarboxylate anions have been synthesized on the basis of p-tert-butylcalix[6]arene, symmetrically functionalized with three butyl(thio)urea groups at the 1,3,5-phenolic positions. The anion complexation has been studied by H-1 NMR titration experiments, FTIR spectroscopy, and FAB mass spectrometry. The receptors bind halide and tricarboxylate anions exclusively through hydrogen bonding in a 1:1 fashion in CDCl3. For halide anions, a preference for bromide over chloride ions is observed, with a highest binding constant K-a of 1.4 x 10(3) M(-1) with receptor 4 containing the urea moieties. Thiourea receptor 5 most strongly binds 1,3,5-benzenetricarboxylate anions (K-a = 2.9 x 10(5) M(-1)) whereas 1,2,4- and 1,2,3-benzenetricarboxylate anions are complexed better by receptor 4 (K-a = 2.3 x 10(4) and 4.7 x 10(4) M(-1), respectively). An explanation for the difference in the binding of halide and tricarboxylate anions by 4 and 5 is given. The mo de of binding in the complex of 5 with 1,3,5-benzenetricarboxylate was elucidated by low-temperature NOESY spectroscopy

Solubilization of NaX salts in chloroform by bifunctional receptors

First the cation, then the anion. This describes the complexation of alkali metal halides with bifunctional receptors like that on the right (R = n‐octyl) based on calix[4]arenes. The uncomplexed ligand has a strong intramolecular hydrogen bond between the urea moieties, which is disrupted by the conformational change induced by complexation of a Na+ ion. Only then is an anion like Cl− bound in the upper portion of the calixarene

Hydroplasticization of latex films with varying methacrylic acid content

The hydroplasticization of coatings of acrylic copolymers with different amounts of methacrylic acid (MAA) was investigated to clarify the role of carboxylic acid functionalities on the change in polymer mobility due to water uptake. The coating Tg as a function of water uptake was studied using dynamic mechanical analysis. The Tg’s decreased with increasing water content, confirming the plasticizing effect of water on the coatings. At relative humidities between 0 and 60% the coating Tg shows a sharper decrease than at higher , an effect that increases with increasing MAA content. This behavior is attributed to the presence of dimers of carboxylic acid in the coatings, which is also observed with FTIR-ATR analyses. Due to water uptake, the dimers are disrupted and form “open” dimers where carboxylic acid groups remain in close proximity and are connected through water molecules. With 1H NMR relaxometry, two T2 relaxation times are found, representing two hydrogen pools with different mobilities. Both mobilities increase with increasing water content, indicating the presence of polymer domains with different hardness. Correlating the T2 relaxation times with the coating Tg’s shows that at higher MAA content the proton mobility as a function of Tg of the soft domains increases with increasing MAA content. Since the polymer proton mobility, and hence the polymer mobility, is expected to scale with the polymer Tg, it is hypothesized that harder domains are present in the coatings, which are not visible in the Ostroff-Waugh decays due to the fast relaxation behavior of these protons

Intraluminar perforated radially expandable drug delivery prosthesis and a method for the production thereof (Patent No.: US 8,267,991 B2)

A radially expandable prosthesis for implantation in a lumen comprises a tubular wall having an inner surface and an outer surface. The tubular wall is provided with cuts to form solid struts which have a thickness and which enables the prosthesis to expand. The solid struts have reservoirs made there-through in the form of perforating holes for containing a therapeutic agent. The perforating holes each have an inner opening and an outer opening of substantially the same size. The prosthesis, including said perforating holes, has a smooth electrochemically polished surface.United States Patent No: US 8,267,991 B2status: publishe