Near infrared light-induced disassembly of polymeric micelles based on methylene blue conjugated polyethylene glycol

Light-sensitive drug delivery systems are considered ideal for applications in the biomedical fields for their ability to release the payload in an on-demand spatiotemporal controlled manner through the manipulation of the light source. Among the broad radiation spectrum, near infrared (NIR) light is considered advantageous compared to UV and visible light, due to its inherently lower photodamage to normal tissues and deeper penetration to lesion areas. In this study, we report a successful synthesis of a polymer capable of undergoing partial degradation upon irradiation with NIR light by conjugating 10-N-carbamoyl linkage methylene blue (MB) moiety, a NIR photocleavable ligand, with polyethylene glycol (PEG). Through effective coupling of MB, a hydrophobic moiety, to the hydrophilic PEG molecule, an amphiphilic polymer was synthesized, as demonstrated by a lowered surface tension (55 mN/m at 0.1% wt/vol). Subsequently, photo-induced reversal of surface activity associated with self-assembled structure disruption, was displayed by surface tension measurements, size distribution analysis, and burst release profile of paclitaxel (PTX) from polymeric micelles upon the exposure to NIR irradiation.     

氟硅酸钠的防结块研究

分折了氟硅酸钠结块的原因，介绍了防结块的措施，并对表面活性剂和惰性物质应用于氟硅酸钠的防结块进行了研究。结果表明，硫酸巴盐或磺酸盐型表面活性剂应用于氟硅酸钠的防结块效果显著，选用复配型表面活性剂，即磺酸盐和脂肪酸盐等的复配液效果更佳，用量为0．12％时能确保氟硅酸钠70d不结块。     

脂肪醇聚氧乙烯-3-醚琥珀酸单酯磺酸盐泡沫性能研究

用罗氏法对脂肪醇聚氧乙烯 3 醚琥珀酸单酯磺酸钠(AESM 3)表面活性剂的泡沫性能进行了系统研究,测定了其在不同浓度、不同温度、不同硬度水中的泡沫性能,并与两种同类表面活性剂的泡沫性能进行了对比。结果表明,AESM 3是一种起泡性与稳泡性皆优的高泡性表面活性剂品种。     

甲烷水合物储气实验研究

利用甲烷水合物储气的实验装置，对高纯度甲烷（甲烷的体积分数为99.9%)气体的水合物形成过程进行了初步的实验研究，获得了水合物形成过程的耗气速度、储气密度与水合物形成条件（压力、表面活性剂种类、水量）的关系。研究结果有利于水合物储存天然气技术的推广和应用，对实现水合物技术的开发、利用和进一步研究水合物形成动力学具有重要价值。     

阴离子表面活性剂测定过程中有关问题的探讨

就亚甲蓝分光光度法测定阴离子表面活性剂应注意的有关问题进行了探讨，改进了测定的方法，具有简便良好的准确度和精密度。     

Improving the properties of water-borne pressure sensitive adhesives by using non-migratory surfactants

The adhesive performance of high solids content water-borne acrylic pressure sensitive adhesives synthesized using polymerizable surfactants (Latemul^®PD-104 and Sipomer^®Pam-200) or a polymerizable stabilizer (Sipomer^®Cops-1) has been studied. The use of a high pH during the polymerization process has a deleterious effect on the final adhesive properties because gel polymer is not formed. Interestingly, at low pH it is found that the surfactant concentration used during the polymerization process has also an effect on the polymer microstructure; the higher the surfactant concentration, the higher the final gel content of the latex. When polymerizable surfactants or a stabilizer are used the peel strength of the final films is considerably improved due to the surfactant incorporation into the polymer backbone and hence reduced surfactant migration to the air-film interface. Work of adhesion and shear adhesion failure temperature (SAFT) are not noticeably affected by surfactant migration but their performance is affected by the surfactant employed.     

Synthesis of Quaternary,Long-Chain N-Alkyl Amides and Their Corrosion Inhibition in Acidic Media

New cationic surfactants were synthesized by the quaternization of a number of straight-chain amide derivatives with triethylamine or pyridine. The corrosion inhibition tests of the surface-active compounds were performed at room temperature for 24 h on carbon steel coupons in acidic media using the gravimetric method. The acidic media used were 1.5 M HCl and 1.5 M H₂SO₄. Almost all of the synthesized cationic surfactants showed efficient inhibition of corrosion in the test. To establish the inhibition efficiencies of the inhibitors, surface characterization studies (contact angle measurements, SEM analysis and optical profilometer images) of the metal coupons used were performed.     

Nanoemulsions containing octyl methoxycinnamate and solid particles of TiO2: preparation,characterization and in vitro evaluation of the solar protection factor

The objective of this work was to develop and evaluate the physical–chemical properties of oil-in-water nanoemulsions for application as nanocosmetics for sun protection. Oil-in-water dispersions were processed by ultrasound (US) to obtain small emulsion droplets. These emulsions were obtained in the presence of commercial nonionic surfactants based on polyoxides and avocado oil as the oil phase. The US generated small but unstable droplets. This problem was solved by using a different surfactant, with a longer ethylene oxide chain, able to promote stabilization by steric mechanisms. The light scattering technique was used to characterize the nanoemulsions by their dispersed droplets’ size, size distribution and variation of distribution with time (stability). Chemical and physical sunscreens – octyl methoxycinnamate (OMC) and titanium dioxide (TiO₂), respectively – were added to the stable system. The anti-UVB activity of the nanoemulsions and their components were evaluated by the method of Mansur et al. (1986) and spectral transmittance. The solar protection factor (SPF) was proportional to the OMC and TiO₂ concentrations. The in vitro OMC release was evaluated, and the presence of TiO₂ in the nanoemulsion did not affect the release profile, which showed the diffusion-dependent kinetics of the active ingredient in the formulation.     

Understanding and Prediction of the Clouding Phenomenon by Spontaneous and Effective Packing Concepts

In this work, we show by which mechanism branching of the hydrocarbon chains influences the cloud point of nonionic, ethoxylated surfactants. The temperature-induced separation into a dilute and a concentrated liquid phase is of liquid–gas type and can be explained by the relative probability of endcaps and branching points of the cylindrical micelles in both phases. The influence of branches on the hydrocarbon chains can be easily understood by means of spontaneous and effective packing concepts, while quantification via hydrophilic/lipophilic balance (HLB), hydrophilic-lipophilic difference (HLD), and HLD-Net Average Curvature requires parametrization. The phase equilibrium above the cloud point phenomenon is equivalent to the Winsor I type phase equilibrium, one of the five known phase equilibria in ternary systems.