Polar Probe Study of Water-Organic Solvent-Macromolecule Emulsifier Aggregates Structure

In this paper, using methyl red as polar probe, a containing LPS macromolecule emulsifier (HBS-1, MW is about 106Da) micellar aggregates in different polar medium (ethanol, n-butyl alcohol, ethylene glycol and DMF) structural properties, and provide a theoretical basis for the mechanism of the emulsified crude oil.

Polar Probe Study of Water-Organic Solvent-Macromolecule Emulsifier Aggregates Structure

In this paper, using methyl red as polar probe, a containing LPS macromolecule emulsifier (HBS-1, MW is about 106Da) micellar aggregates in different polar medium (ethanol, n-butyl alcohol, ethylene glycol and DMF) structural properties, and provide a theoretical basis for the mechanism of the emulsified crude oil.

Studies on Improving PP Fiber Reinforced Concrete

Grafting method was used to modify polypropylene (PP) fiber to enhance the fiber reinforced concrete in this study. Polyacrylamide (PAM) was grafted onto PP surface by UV radiation using benzophenone (BP) as a photoinitiator. The microstructure of PP, and the interaction force between PP and the polar probe were observed with an atomic force microscopy (AFM). Experimental results showed that the roughness of PAM-grafted PP surface decreased significantly in comparison with that of the untreated PP surface. In addition, instead of smooth force curve as that of the untreated PP, the interaction between the probe and PAM-grafted PP surface appeared an oscillation. The above results gave the evidences that PAM had been successfully grafted onto the PP surface as discussed . The high hydrophilic property of PAM modifies the surface property of PP fiber and strengthens PP fiber reinforced concrete.

Use of Contact Angle Hysteresis in Estimating Thin Polymer Film Surface Energy and Wettability

A recent surface energy estimation method [1] interpreting contact angle hysteresis measurements was used to estimate surface energy of various commercially important polymer films including UV radiation cross-linked acrylic based monomer systems. The validity of the method was tested on highly hydrophobic non-polar amorphous fluoro-polymers using a number of polar and low surface tension liquids. Contact angle hysteresis was present on these surfaces even though surface morphology of the solution processed fluoro-polymers is close to ideal. Estimated surface energies using such probe liquids were consistent varying slightly with the probe liquid type. On such highly ordered and non-polar polymer surfaces use of polar and low surface tension liquids results in accurate surface energy estimation. However, use of polar probe liquids commonly employed in surface energy estimation methods, such as, Harmonic mean (HM), Geometric mean (GM) or Lewis Acid-Base method (LWAB) on polar surfaces such as polyester resulted in inconsistent surface energy values. To strengthen this observation, the ASTM surface energy estimation procedure (ASTM D2578 04a) developed for polyethylene and polypropylene surfaces (both non-polar) was employed on a sample polar polyester surface using the ASTM probe liquids. Results showed inconsistent surface energy values supporting the conclusion that care must be exercised during use of polar probe liquids in estimating surface energy on polar polymers with the contact angle hysteresis method. Finally, UV radiation cross-linkable acrylic polymer surface energies were estimated with the hysteresis method. Surface energy results were consistent based on five different probe liquids. It was observed that surface energy of the cross-linked monomer networks decreased slightly with increasing UV curing time.

Labelling of egg phosphatidylcholine vesicles and myelin membrane with a photoreactive lipophilic reagent

The preparation and isolation of [3H]phenyl azide, a photosensitive non-polar probe, is reported. The reagent partitions into the lipid bilayer of egg phosphatidylcholine vesicles and bovine myelin membranes. On photoactivation to generate the nitrene grouping, as much as 90% of the covalently attached label is associated with the fatty acyl residues of the constituent phospholipid molecules. The remainder is found in the polar head groups. The cholesterol component of myelin membranes is also heavily labelled. These results suggest that such reagents may be used to probe the hydrophobic regions of natural membranes.