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The surface activity and aggregation behavior of a synthesized nicotinic acid based anionic surfactant, sodium 2-dodecylnicotinate, were studied in aqueous solution. The self-assembly formation was investigated by use of a number of techniques, including surface tension and conductivity measurements, fluorescence spectroscopy, dynamic light scattering measurement, gel permeation chromatography, and microscopy. The amphiphile exhibits two breaks in the surface tension vs concentration plot, indicating stepwise aggregate formation and thus producing two values of the aggregation concentration. Stepwise aggregation of the amphiphile was further confirmed by steady-state fluorescence spectroscopy using pyrene as a probe molecule, and also the micropolarity of the aggregates was determined. The rigidity of the microenvironment was estimated by determining steady-state fluorescence anisotropy using 1,6-diphenyl-1,3,5-hexatriene as a fluorescence probe molecule. The average hydrodynamic radius and size distribution of the aggregate suggest formation of larger aggregates in aqueous solution. The formation of vesicles in water was established by conductivity measurement and a dye entrapment experiment. The entrapment of a small solute and the release capability have also been examined to demonstrate these bilayers form enclosed vesicles. Transmission electron micrographs revealed the existence of closed vesicles and closed tubules in aqueous solution. Therefore, for the first time, it has been observed that this simple single-chain nicotinic acid based amphiphile spontaneously assembles to vesicles in aqueous solution.

The surface activity and aggregation behavior of two synthesized boronic acid based anionic surfactants, sodium salt of 2-dodecyl pyridine-5-boronic acid (SDDPB) and sodium salt of 2-oxydodecyl pyridine-5-boronic acid (SODDPB), were studied in buffer solution at pH 9 and 13 containing carbohydrates. The self-assembly formation was investigated by use of a number of techniques including surface tension, conductivity, fluorescence spectroscopy, dynamic light scattering, X-ray diffraction, and transmission electron microscopy (TEM). Both of the amphiphiles exhibit a single break in the surface tension vs log(concentration) plots, indicating existence of one critical aggregation concentration. Steady state fluorescence spectroscopy was used to determine the polarity indexes using pyrene and the rigidity of the microenvironments of the aggregates using 1,6-diphenyl-1,3,5-hexatriene (DPH) as fluorescence probe molecules. The pKa's of both amphiphiles were determined in buffer solutions of different pH's. XRD studies were performed to shed light on the morphology of the self-assemblies. TEM micrographs revealed the existence of vesicles for both the amphiphiles in buffer solution of pH 9, but at pH 13, TEM pictures indicate the existence of closed vesicles in SDDPB solution and at concentrated solution the vesicles are fused to form sponge-like micelles. After aging the vesicular solution of pH 13 of SDDPB, the closed vesicles are destroyed. In contrast, for SODDPB at pH 13, TEM pictures suggest the existence of spherical and complex micelles in solution which were further transformed into crystal-like structure upon aging. The average hydrodynamic radii were determined by dynamic light scattering measurement. Therefore, for the first time, we have successfully synthesized two new surfactants containing pyridyl-boronic acid as a headgroup which shows remarkable tuning of morphology in two different pH's and in the presence of two different carbohydrates.

In this work, two boronic acid based amphiphiles, Sodium salt of 2-amidodecylpyridine-5-boronic acid (SADPB) and Sodium salt of 2-amidododecylpyridine-5-boronic acid (SADDPB) have been synthesized and their gel-emulsion property in organic solvents were investigated. The good gelation ability of the amphiphiles was confirmed by low minimum gelation concentration (MGC) and high gelation number (N gel ) values. Theoretical study established that introduction of amide linkage in the amphiphilic structure dismantles aggregate formation. The gelemulsions are stable towards mechanical and thermal re-sponses. The gelation process is also dependent on the nature of solvent and type of amphiphiles. The morphology of gelemulsions is highly dependent on the concentration of the amphiphile. The prepared gel-emulsions are able to encapsulate and release biomolecule vitamin B 12 and anticancer drug doxorubicin at room temperature. Both vitamin B 12 and doxorubicin exhibited retention of their structures and activity which has been recognized this new type of boronic acid based amphiphiles as efficient drug delivery vehicles.[a] Dr.

The fabrication of adsorbents for volatile organic compounds (VOCs) always attains significant research interest for the industrialized civilization. Herein, we report the fabrication of a new class of porous polymeric monolith for the efficient adsorption of VOCs. In this case, a gel emulsion stabilized by poly­(oligo­(ethylene glycol) methyl ether methacrylate)-b-polystyrene (POEGMA-b-PS), an amphiphilic block copolymer (BCP), was successfully used as the template for the development of a porous monolith having a porosity in the range of 5–50 μm. A reversible addition–fragmentation chain transfer (RAFT) polymerization technique was adopted for the synthesis of BCP with varying PS block length. The BCPs were used as the stabilizer for water-in-oil gel emulsion consisting of >90% dispersed phase without using any costabilizer. Morphology and thermal and rheological behavior of the prepared gel emulsions were found to be dependent on the PS block length in the BCP as analyzed in FE-SEM, DSC, and rheometry. Porous polymeric monoliths were prepared by polymerizing gel emulsions with a mixed oil phase containing a styrene monomer, cross-linker, and radical initiator. The resulting monoliths had a minimum density of 0.08 g/cm3. Those monoliths were found to have very high resistance to water, showing a water contact angle of ∼120°, while they can effectively adsorb a wide range of VOCs like benzene, toluene, xylene, ethylbenzene, chloroform, tetrahydrofuran, acetone, formaldehyde, hexane, etc. and also attain reusability with similar efficiency.

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Three nicotinic acid amphiphiles, sodium 6-octylnicotinate (SONA), sodium 6-decylnicotinate (SDNA), and sodium 6-decylnicotinic glycinate (SDNAG), have been synthesized, and the effect of hydrocarbon chain length as well as amide linkage on the self-assembly properties in aqueous solutions have been investigated using a number of techniques, including tensiometry, fluorometry, FT-IR spectroscopy, 1H NMR spectroscopy, UV–vis spectroscopy, dynamic light scattering, X-ray diffraction (XRD), and transmission electron microscopy (TEM). Tensiometry measurements reveal the presence of two critical aggregation concentrations (CACs) for simple aliphatic chain amphiphiles, whereas a single CAC was obtained when glycine was introduced in the headgroup. Gel permeation chromatography studies indicate the presence of closed bilayer aggregates for all of the amphiphiles in aqueous solutions. XRD spectra indicate the presence of a non-interdigited bilayer structure. The presence of bilayer vesicles was confirmed by TEM measurements. Permeability of the bilayer membranes of the vesicles were investigated using the model water-soluble dye methylene blue. The vesicles obtained with nicotinic acid amphiphiles could be used as versatile carriers suitable for both hydrophobic and hydrophilic molecules.

A cholesteric liquid crystal (ChLC) in a confined space has attracted significant scientific interest and has potential applications. ChLC microspheres have been obtained by devising processing such as a microfluidic technique. Herein, we adopted the self-assembly approach for the spontaneous formation of cellulosic ChLC microspheres. A functional block copolymer (BCP) was grafted to hydroxypropyl cellulose (HPC), making it amphiphilic to self-assembly in a w/o emulsion. The HPC segment aggregated in the aqueous phase under lyotropic conditions and produced the ChLC microspheres dispersed in the oil phase. The microspheres exhibited a topological transition between radial and bipolar while altering the molecular structure in terms of the molecular weight of BCP and the degree of substitution of HPC. The coexistence of inorganic salts in the aqueous HPC lyotropic phase changed the mesophase behavior as well. Such cellulosic ChLC microspheres will present opportunities to develop biobased optical devices and stimuli-responsive biomedical materials.