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[en] Four multialkoxy-functionalized siloxane base-polymers were synthesized through either hydro-silylation or condensation reactions in order to prepare multi-networked siloxane polymers having appropriate physical properties for protective coating in fabrications of electronics. Formulations of 4 base-polymers gave coating materials and. Product A showed well-controlled flowing and leveling properties, and product A-2 was successfully applied to protective insulating coating for junction areas of connectors and chips in PDP controller. Tack free time, extrusion rate, dielectric breakdown voltage, hardness, thermal stability, water resistance and flame resistance of products and were examined
[en] The aim of the studies was to obtain thin films of SiO2 from hexamethyldisiloxane (HMDSO) using discharges stabilized with a dielectric barrier (DBD) under atmospheric pressure. The process was carried out at frequency of 5 kHz. Films were deposited from the following gas mixtures: HMDSO + N2, HMDSO + Ar +O2, HMDSO+Ar+N2O, HMDSO + Ar + NH3. The influence of the gas mixture composition on of the film properties were studied. (author)
[en] The current status of the chemistry of metallasiloxanes is surveyed. Synthetic methods affording the metallasiloxane fragments and specific transformations of metallasiloxanes governed by the coordination properties of the metal site are analysed. The emphasis is placed onto the formation of compounds with the metallasiloxane fragments and rearrangements of these fragments. Principles of the design of catalytic systems based on metallasiloxanes, in particular, containing low-coordinated metal sites, are generalised.
[en] We investigated the concentrations and profiles of 15 siloxanes (four cyclic siloxanes, D4-D7; 11 linear siloxanes, L4-L14), four synthetic musks (two polycyclic musks, HHCB and AHTN; two nitro musks, MX and MK), and HHCB-lactone, in 158 personal care products marketed in China. Siloxanes were detected in 88% of the samples analyzed, at concentrations as high as 52.6 mg g-1; Linear siloxanes were the predominant compounds. Among synthetic musks, more than 80% of the samples contained at least one of these compounds, and their total concentrations were as high as 1.02 mg g-1. HHCB was the predominant musk in all of the samples analyzed, on average, accounting for 52% of the total musk concentrations. Based on the median concentrations of siloxanes and musks and the average daily usage amounts of consumer products, dermal exposure rates in adults were calculated to be 3.69 and 3.38 mg d-1 for siloxanes and musks, respectively. - Highlights: → Siloxanes and synthetic musks are determined in personal care products. → Highest siloxane concentration was 52.6 mg g-1. → Highest musk concentration was 1.02 mg g-1. → Daily dermal exposure rates of siloxanes and musks were in mg levels. → Dermal exposure is a major pathway of human exposure to siloxanes and musks. - Dermal application of several personal care products is a major source of human exposure to cyclic and linear siloxanes.
[en] We present a simple and effective mold cleaning method for nanoimprint lithography. Polydimethylsiloxane (PDMS) prepolymer is spin-coated onto a contaminated imprint mold, thermally cured in an ambient environment, and then peeled off afterwards. Contaminants of 100 s μm to sub-50 nm sizes are effectively cleaned within one cycle. During the cleaning process, a very thin PDMS film (1–2 nm) is uniformly coated onto the mold surface, serving as a protection and anti-sticking layer. (paper)
[en] A passively Q-switched fiber laser using a novel saturable absorber (SA) of Siloxane has been demonstrated. The modulation depth of the SA is measured to be 4.87%. Based on such an SA, the Q-switched operation in the laser has been achieved. The average output power of the Q-switched fiber laser is 0.78 mW with a pulse repetition rate of 21.3 kHz. The pulse energy goes up to 36.62 nJ when the pump power of the laser is 200 mW. The Q-switched laser exhibits the performances of self-starting, good stability, and high pulse energy. To the best of our knowledge, it is the first demonstration of the passively Q-switched laser based on a siloxane SA. (letter)
[en] We report on the development of a PDMS-SMA composite whose surface micro wrinkles can be dynamically programmed by an electrical current supplied to the SMA wire. It is advantageous over other techniques for surface topographical modulation, including portability, real-time programmability, no requirement for specific surface chemistry, operability under ambient conditions, and relative ease of control. A simplified mechanical model is also developed to describe the force-deflection balance of the PDMS-SMA composite. The wavelengths and amplitudes of the wrinkles when different currents applied to the SMA are characterized, and the experimental results agree with the theoretical model. The developed composite device can be applied to programmable modulations of surface adhesion, friction, wettability, etc. (paper)