The amphiphilic polymer-grafted silica was newly prepared as a stationary phase in high-performance liquid chromatography. Poly(4-vinylpyridine) with a trimethoxysilyl group at one end was grafted onto porous silica particles and the pyridyl side chains were quaternized with 1-bromooctadecane. The obtained poly(octadecylpyridinium)-grafted silica was characterized by elemental analysis, diffuse reflectance infrared Fourier transform spectroscopy and Brunauer–Emmett–Teller analysis. The degree of quaternization of the pyridyl groups on the obtained stationary phase was estimated to be 70%. The selective retention behaviors of polycyclic aromatic hydrocarbons including some positional isomers were investigated using poly(octadecylpyridinium)-grafted silica as an amphiphilic polymer stationary phase in high-performance liquid chromatography and results were compared with commercially available polymeric octadecylated silica and phenyl-bonded silica columns. The results indicate that the selectivity toward polycyclic aromatic hydrocarbons exhibited by the amphiphilic polymer stationary phase is higher than the corresponding selectivity exhibited by a conventional phenyl-bonded silica column. However, compared with the polymeric octadecylated silica phase, the new stationary phase presents similar retention behavior for polycyclic aromatic hydrocarbons but different retention behavior particularly for positional isomers of disubstituted benzenes as the aggregation structure of amphiphilic polymers on the surface of silica substrate has been altered during mobile phase variation.

A new strategy for creating the energy transfer spectral conversion thin film by using fluorophore-functionalized molecular gelation is proposed. This is based on the facts that nanofibrillar phase separation of the self-assembling pyrene derivative as a fluorophore is formed in a bulk polymer-containing organic gel, and consequently that the phase-separated nano domain in a polymer thin film is enough small to keep the transparency but also extremely high Storks shift is gained by efficient excimer formation through highly ordered stacking among the pyrene moieties. When the phase separation-mediated functional polymer is applied as spectral conversion films (SCFs) for copper–indium–gallium–selenide (CIGS) solar cell, the SCF-covered solar cell exhibits significant improvement of power conversion efficiency by increase of photocurrent. In this paper, the FRET efficiency and emission wavelength are also demonstrated to be thermotropically switchable since order-to-disordered transitions are essential characteristics of as non-covalent low molecular assembling.

A novel sulfonic-azobenzene-functionalized amphiphilic silica material was synthesized through the preparation of a new sulfonic azobenzene monomer and its grafting on mercaptopropyl-modified silica by a surface-initiated radical chain-transfer reaction. The synthesis was confirmed by infrared spectra, elemental analysis, and thermogravimetric analysis. This new material was successfully applied as a new kind of mixed-mode stationary phase in liquid chromatography. This allows an exceptionally flexible adjustment of retention and selectivity by tuning the experimental conditions. The distinct separation mechanisms were outlined by selected examples of chromatographic separations in the different modes. In reversed-phase liquid chromatography, this new stationary phase presented specific chromatographic performance when evaluated using a Tanaka test mixture. Seven dinitro aromatic isomers, four steroids, and seven flavonoids were separated successfully in simple reversed-phase mode. This stationary phase can also be used in hydrophilic interaction chromatography because of the existing polar functional groups; for this, nucleosides and their bases were used as a test mixture. Interestingly, the same nucleosides and bases can also be separated in per aqueous liquid chromatography using the same stationary phase. Three ginsenosides including Rg1, Re, and Rb1 were successfully separated in hydrophilic mode. There is the potential for more applications to benefit from this useful column.

A new approach for fabricating donor–acceptor assembled systems is demonstrated, based on J-type ordered aggregation of a low-molecular zinc porphyrin derivative and subsequent integration of a pyridylated fullerene derivative with coordination and orientation onto the porphyrin aggregates. This system achieves unusually high efficiencies in fluorescence quenching during one-to-one mixing of the donor and acceptor. Moreover, the Stern–Volmer constant (K_SV) and association constant (K) of this system are 2520 and 56 times higher, respectively, than those of the corresponding nonassembled system. The quenching efficiency is thermotropically switchable, since ordered-to-disordered transitions are essential characteristics of noncovalent low molecular assemblies.

A new ionic-liquid monomer, 1-vinyl-3-octadecylimidazolium bromide ([C₁₈VIm]Br), was prepared and polymerized on porous silica particles by means of a surface-initiated radical chain-transfer reaction. Further modification for functionalization was performed through the exchange of counteranions from bromide to methyl orange (MO). Two new silica–poly(octadecylimidazolium) (Sil-PImC₁₈) hybrid materials (Sil-PImC₁₈-Br and Sil-PImC₁₈-MO) were synthesized and characterized by elemental analysis, thermogravimetric analysis, diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), and solid-state ¹³C CP/MAS NMR spectroscopy. Sil-PImC₁₈-MO presented ultra-high shape selectivity for constrained isomers of polycyclic aromatic hydrocarbons (PAHs) both in reversed- and normal-phase HPLC when used as the stationary phase. Fundamental aspects of the molecular shape selectivity were evaluated by using Standard Reference Material (SRM) 869b; the column selectivity test mixture for liquid chromatography. The impact of this phase was also demonstrated by the separation of SRM 1647e (16 priority pollutant PAHs) and several steroid isomers. Enhanced selectivity could be explained by the highly oriented arrangement between the octadecylimidazolium chain and a rigid segment of MO. These findings may open a new window of research for the design of materials used in chromatographic supports, solid extraction, catalysis, and electrolytes by simple modifications of the counterions in the poly(ionic liquid) analogous phase.

The L-glutamide derivative with double long-chain alkyl groups and a pyrenyl head group (Pyr-lipid) worked as organogelator in benzene and cyclohexane. Gelation was brought about through network formation with well-developed fibrous aggregates based on lipid membrane-like highly-oriented structures. Gelation was observed in polymerizable monomers such as methyl methacrylate (MMA) and styrene (St). Extremely intense CD spectra were observed at the absorption band of pyrenyl group in a monomer solution at gel-forming temperature, but the intensity decreased remarkably at the sol-forming temperature. The transparent solid sheet was obtained by photo-irradiation to the MMA gel in a quartz cell. More than 99% of MMA was polymerized even in the gel state and the weight-average molecular weight (M_w) of the resultant polymer was 7.2 × 10⁴ g mol⁻¹. CD spectra indicated that chirally-oriented structures in the gel state were maintained after polymerization of MMA and were stable at the temperature above the original gel-to-sol transition temperature. Fluorescence spectra of Pyr-lipid in the monomer solutions supported that the pyrene excimer was formed in the lipid aggregates and the stabilization of the excimer formation was achieved by polymerization of MMA in the gel state.

Glutamine derivative 1 with two-photon absorbing units has been synthesized and was found to show gelation ability in some solvents. Its self-assembly in the gel phase could be controlled by the solvent and speed of gelation. For example, in DMSO the organogelator self-assembled into H-aggregates with weak exciton coupling between the aromatic moieties. On the other hand, in DMSO/diphenyl ether (1:9, v/v) the molecules formed 1D aggregates, but with strong exciton coupling due to the small distance between the chromophores. Moreover, the formation of these two kinds of aggregates could be adjusted by the ratio of DMSO to diphenyl ether. In DMSO/toluene, DMSO/butanol, DMSO/butyl acetate, and DMSO/acetic acid systems similar results were observed. Therefore, conversion of the packing model occurs irrespective of the nature of the solvent. Notably, a unique sign inversion in the CD spectra could be realized by controlling the speed of gelation in the DMSO/diphenyl ether (1:9, v/v) system. It was found that a low speed of gelation induces the gelator to adopt a packing model with strong π–π interactions between the aromatic units. Moreover, the gels, when excited at 800 nm, emit strong green fluorescence and the quantum chemical calculations suggest that intramolecular charge transfer leads to two-photon absorption of the gelator molecule.

The monomer N′-octadecyl-N^α-(4-vinyl)-benzoyl-L-phenylalanineamide (4) based on L-phenylalanine has been simply but effectively synthesized, and its self-assembling properties have been investigated. FTIR and a variable-temperature ¹H NMR spectroscopic investigation demonstrated that the aggregation of compound 4 in various organic solvents is due to the formation of intermolecular hydrogen bonds among the amide moieties. UV/Vis measurements indicated that the multiple π–π interactions of the phenyl groups also contribute to the self-assembly. As was observed by ¹³C cross-polarization magic-angle spinning (CP/MAS) NMR and variable-temperature ¹H NMR measurements, the ordered alkyl chains also played an important role in the molecular aggregation by van der Waals interactions. Compound 4 was polymerized by surface-initiated atom transfer radical polymerization from porous silica gel to prepare a packing material for HPLC. The results of thermogravimetric analysis showed that a relatively large amount of polymer was grafted onto the silica surface. The organic phase on silica was in a noncrystalline solid form in which the long alkyl chain exists in a less-ordered gauche conformation. Analysis of chromatographic performance for polyaromatic hydrocarbon samples showed higher selectivity than conventional reversed-phase HPLC packing materials.