Narrow Results

Dust and other environmentally suspended particles deposited on the solar panels reduce the sunlight to photovoltaic cells, reducing the total energy outcome. A dust-reflecting coating keeps a cleaner surface, thus enhancing light absorption and improving the overall energy outcome. This study synthesized the sol–gel of SiO₂, MgF₂, and TiO₂ and made the coating on the glass substrate by SiO${}_2+{\mathrm{\text{MgF}}}_2$, SiO${}_2+{\mathrm{\text{TiO}}}_2$, and MgF${}_2+{\mathrm{\text{SiO}}}_2+{\mathrm{\text{TiO}}}_2$ using sol–gel dip coating and spin coating method. Coatings that occurred on the glass sample surfaces were identified by using FTIR analysis. Five of the above six coatings made using different mixtures have increased transmittance than pure glass, while one SiO${}_2+{\mathrm{\text{MgF}}}_2$ spin coating reduced the transmittance. The minimum water contact angle of 37.69^∘ was found on the SiO${}_2+{\mathrm{\text{TiO}}}_2$ spin-coated surface, and the maximum contact angle was 72.10^∘ on the MgF₂ dip-coated surface. This shows that the self-cleaning properties in SiO${}_2+{\mathrm{\text{TiO}}}_2$ spin-coated surfaces are maximum and minimum in MgF₂ dip-coated surfaces. The angle found by the test shows that spin coating is a better technique than dip coating for hydrophilic surface coating. This was due to the more homogenous coating on the spin-coated sample surfaces. There was less accumulation of dust found on the coated surfaces compared to non-coated glass sample surfaces.

Aqueous silk fibroin (SF) sol is a colloidal solution. With the colloidal hydration layer and electrostatic repulsion, the SF sol can hardly make the efficient collision/assembly among micelles and perform like a following sol for a long time. In this paper, hydrophilic silk-based sequences (HSF) derived from SF molecules were obtained by immersing the dried SF condensates with water and extracting the dissolving fraction. The HSF was obtained by immersing the SF condensate dried at the temperature of $20$–$25^{\circ }\mathrm{\text{C}}$ and relative humid of 55–60% in water and collected the lixivium. The dissolving ratio was about 30%. The HSF sol (0.5%, w/v) self-assembled into the mesoscopic 3D nanofibrous network within 8 h. The obtained HSF nanofibers were 10–100 $\mu \mathrm{\text{m}}$ in length and 50–100 nm in diameter. The HSF nanofiber possesses similar hierarchical structure consisting of nanofibrils bundles to the native silk fiber. There were significant aggregation structure transitions from random coil to $\beta$-sheet and amorphous chains to Silk II crystal aggregation during the formation of HSF nanofibers. The HSF nanofiber holds the potential to give further insight into the reconstruction of native silk in vitro and the fabrication of tough silk-based biomaterials.

The surface modification mechanism of polyvinyl chloride (PVC) by ozonation was investigated to study the selective hydrophilization of PVC surface among other plastics. Infrared analysis confirmed the increase of hydrophilic groups. XPS analysis revealed that the increase was due to the structural change in chlorine group in PVC to hydroxylic acid, ketone, and carboxylic groups by ozonation. This chemical reaction by ozone could occur only for polymers with chlorides in its structure and resulted in the selective hydrophilization of PVC among various polymers.

Molecular interaction dynamics at liquid–liquid interface (LLI), involved nondispersive solution as compared with the interaction in bulk phase. Thereby, interfacial tension (IFT, mN/m) of LLI for four saturated hydrocarbons, six alcohols, and three cationic surfactants are reported at 298.15 K. The pentane, hexane, heptane, octane hydrocarbons and pentanol, hexanol, heptanol, 1-octanol, 2-octanol, and 1-decanol alcohols were used and IFT data were compared with 4 mm kg^-1 dodecyltrimethylammoniumbromide (DTAB), trimethylsulfoxoniumiodide (TMSOI), methyltrioctylammoniumchloride (MTOAC) surfactants studied in benzene–water LLI. The IFT data are noted as hydrocarbons > DTAB > TMSOI > alcohols > MTOAC. The hydrocarbons and alcohols decreased IFT within 16 to 49% and 87 to 92%, respectively, whereas the surfactants within 78.3 to 95.9%. The alcohols developed interaction similar to surfactants and are denoted as nonionic surfactants for making mixtures of low IFT with hydrophilic and hydrophobic interactions to the level of the surfactants. The pentanol and MTOAC caused similar decrease in IFT so the pentanol developed the hydrophilic and hydrophobic interactions of the strength of MTOAC. Comparatively, the hydrocarbons showed lower decrease but the octane showed 49% decrease in IFT. Thus, the hydrocarbon with longer alkyl chain and the alcohol with shorter behave as good surfactants. The hydrocarbons with inductive effect on sigma bond between carbon atoms in alkyl chain also weakened the IFT and influenced the hydrophobic interactions. The MTOAC with four octyl units reduced 96% IFT so inductive effects monitor LLI dynamics.

The title complex cation, [Sb(pc)(OH)₂]⁺, (pc = phthalocyaninate, C₃₂H₁₆N₈^2-) has been prepared by oxidizing [Sb(pc)]I₃ with tert-butyl perbenzoate and isolated as hexafluorophosphate and triflate salts. These salts are relatively well-soluble in polar solvents (e.g.CH₂Cl₂, acetonitrile, acetone) without detectable aggregation. In particular, they dissolve relatively well in ethanol and methanol in which [Sb(pc)Br₂]⁺ or [Sb(pc)Cl₂]⁺ salts are poorly soluble whereas they have extremely low solubility in 1-chloronaphthalene and CHCl₃, unlike the bromo or chloro analogs. The spectral properties of [Sb(pc)(OH)₂]⁺ have been investigated by optical absorption and magnetic circular dichroism spectroscopy. Although its Q band tends to appear at a longer wavelength in a solvent with a larger refractive index, as is the case for its Br and Cl analogs, the Q band positions in donor solvents deviate considerably from linear correlation between Onsager's solvent polarity function. In the Soret band region, spectra of [Sb(pc)(OH)₂]⁺ are different in CH₂Cl₂ and acetonitrile, particularly around the B1/B2 bands, unlike the bromo and chloro analogs. The solvent dependence of absorption spectra and the difference in solubility suggests that the presence of the axial hydroxyl groups endows the phthalocyanine macrocycle with considerable hydrophilicity. It also suggests that there are some specific chemical interactions between the axial hydroxyl groups and the surrounding donor solvent molecules.

Advances in chlorin synthetic chemistry now enable the de novo preparation of diverse chlorin-containing molecular architectures. Five distinct molecular designs have been explored here, including hydrophobic bioconjugatable (oxo)chlorins; a hydrophilic bioconjugatable chlorin; a trans-ethynyl/iodochlorin building block; a set of chlorins bearing electron-rich (methoxy, dimethylamino, methylthio) groups at the 3-position; and a set of ten 3,13-disubstituted chlorins chiefly bearing groups with extended π-moieties. Altogether 23 new chlorins (17 targets, 6 intermediates) have been prepared. The challenge associated with molecular designs that encompass the combination of "hydrophilic, bioconjugatable and wavelength-tunable" chiefly resides in the nature of the hydrophilic unit.

Experiment on the surface characteristics of polymer films (PC, PET, EVA) treated by atmospheric pressure plasma has been conducted. As the process parameters, we chose frequency, gas flow and treatment time. By measuring the contact angle, we scrutinized the effects of these parameters on the hydrophilic surface characteristics of polymer materials and found the optimum operating condition of each polymer for the highest hydropilicity. In the case of PC substrate, the contact angle was changed from 83.5 ± 1.1° (before plasma treatment) to 30.4 ± 0.4° (after plasma treatment) at the optimum operating condition of 30 kHz, CDA 0.6%, and repeated number of 7. In the case of PET substrate, the contact angle change was found from 59 ± 1.1° to 23.5 ± 1.7° at 20 kHz, CDA 0.6%, and repeated number of 7. In the case of EVA substrate, the contact angle of 84 ± 0.6° changed to 44.2 ± 1.2° at 30 kHz, CDA 0.6%, and repeated number of 7. The long-term stability of the hydrophilic surfaces and section morphology were also examined by SEM. As a roll-to-roll application, the adhesion force between PET and UV resin was measured to show initial increase according to the plasma treatment time, i.e., repeated number but finally saturated to show no meaningful change, which is in line with the behavior of the contact angle according to plasma treatment time.

A simple nonaqueous reaction scheme for transforming the surface of plastics from hydrophobic to hydrophilic is presented. The chemical modification is achieved by the base-catalyzed trans-esterification of polyethylene terephthalate (PET), which is a commonly used plastic. Its use in blood collection tubes is discussed. The surface modification is permanent, inexpensive, rapid, and does not release contaminants. It also causes no optical or mechanical distortion of the plastic. This work demonstrates the power of chemistry to transform common materials.

Self-assembled-monolayer (SAM) has a special characteristic that it can template the growth of inorganic crystals under the ordinary conditions, which is similar to the action in the living bodies. In the present study, the precipitation of apatite on "OH" terminated SAM surface(silicon) was observed after soaked in SBF (Simulated Body Fluid). On the contrary, little apatite was formed on the SAM surface with "Phenyl" headgroups. PTCS (Phenyltrichlorosilane) was employed to make "Phenyl" terminated hydrophobic SAM . After UV irradiation for 2 hours, "-OH" terminated hydrophilic SAM was obtained. The effects of such factors as pH and Ca/P molar ratio in SBF solution, soaking temperature and time .etc, on the crystallization of apatite were investigated. XRD results revealed the preferentially oriented crystallization of apatite on "OH" terminated SAM.

A simple nonaqueous reaction scheme for transforming the surface of plastics from hydrophobic to hydrophilic is presented. The chemical modification is achieved by the base-catalyzed trans-esterification of polyethylene terephthalate (PET), which is a commonly used plastic. Its use in blood collection tubes is discussed. The surface modification is permanent, inexpensive, rapid, and does not release contaminants. It also causes no optical or mechanical distortion of the plastic. This work demonstrates the power of chemistry to transform common materials.