Infrared Spectroscopic Studies on the Molecular Orientation of Vacuum-Deposited Thin Films of Poly(dimethylsilane) and a Linear Oligosilane

Shimomura, Masaki; Okumoto, Hajime; Kaito, Akira; Ueno, Katsuhiko; Shen, Jingshu; Ito, Kohzo

doi:10.1021/ma980235j

Cited by 24 publications

(13 citation statements)

References 35 publications

(66 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Other absorptions are characteristic of PDMS. 51 For polyurethanes and polyureas, two carbonyl stretching peaks usually occur from 1500 to 2000 cm −1 . The lower frequency peak is assigned to H-bonded carbonyls while the higher frequency peak is due to "free" carbonyls.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

PDMS–Fluorous Polyoxetane–PDMS Triblock Hybrid Elastomers: Tough and Transparent with Novel Bulk Morphologies

2012

View full text Add to dashboard Cite

PDMS-3F-1.1-PDMS and PDMS-3F-4.5-PDMS triblock hybrid elastomers are investigated, wherein (1) 3F-1.1 and 3F-4.5 are poly(3-methyl-3-trifluoroethoxymethyl)-1,3-propylene oxide with M n = 1.1 or 4.5 kDa, (2) segments are linked by urethane/urea forming reactions, and (3) the intermediate PDMS-3F-PDMS aminopropyl end segments are end-capped with isocyanatopropyltriethoxysilane. After condensation cure, PDMS-3F-PDMS triblock hybrids (A-1.1 and A-4.5) form robust elastomers. In a second set, bis(triethoxysilylethane), BTESE, was incorporated to probe effects of increased siliceous domain content (B-1.1, B-4.5). All compositions are optically transparent due to nearly identical refractive indexes for 3F and PDMS segments. TM-AFM images for A-4.5, A-1.1, and B-4.5 fracture surfaces reveal microscale bulk phase separation. The A-4.5 triblock hybrid shows a particularly interesting morphology comprised of 2−3 μm ovaloids (low modulus) surrounded by a higher modulus matrix. A model is proposed for this microscale morphology based on the relative rates of physical network formation (PN, H-bonding) and chemical network formation (CN, SiO 1.5 ) during coating deposition Despite low hard segment weight percents (2.6−3.5) the hybrid triblocks have moderate toughness with strain at break ranging from 260 to 492%. Triblock hybrid elastomer B-1.1 has the highest −SiO 1.5 wt % (mostly from BTESE) and lowest 3F wt % (3F-1.1). No sign of microscale phase separation is observed by TM-AFM imaging, and a separate T g for the 3F segment is not detected by DMA; these findings are ascribed to network constrained phase separation of that results in 3F being incorporated in an "interphase". The absence of a separate T g for 3F leads to a gradual decrease in storage modulus (8 to 1.4 MPa) from −90 to 150 °C. In contrast to the complex bulk morphology, TM-AFM imaging shows the hybrid surfaces are devoid of microstructural features attributable to phase separation. Based on contact angle measurements and XPS analysis, the outermost surface for all PDMS-3F-PDMS hybrid triblocks elastomers is dominated by PDMS.

show abstract

Section: ■ Results and Discussionmentioning

confidence: 99%

PDMS–Fluorous Polyoxetane–PDMS Triblock Hybrid Elastomers: Tough and Transparent with Novel Bulk Morphologies

2012

View full text Add to dashboard Cite

show abstract

“…One promising candidate is infrared (IR) spectroscopy, which is an important method for the characterization of polymer conformation [277], orientation [278], and solvent effects [279]. Newer developments in IR spectroscopy include time-resolved [280,281] and two-dimensional techniques [282,283] for dynamic processes in polymers, such as conformational changes, diffusion, and polymerization.…”

Section: Laser Application Of Polymersmentioning

confidence: 99%

Laser Application of Polymers

Lippert

2004

Polymers and Light

148

View full text Add to dashboard Cite

Laser ablation of polymers has been studied with designed materials to evaluate the mechanism of ablation and the role of photochemically active groups on the ablation process, and to test possible applications of laser ablation and designed polymers. The incorporation of photochemically active groups lowers the threshold of ablation and allows high-quality structuring without contamination and modification of the remaining surface. The decomposition of the active chromophore takes place during the excitation pulse of the laser and gaseous products are ejected with supersonic velocity. Time-of-flight mass spectrometry reveals that a metastable species is among the products, suggesting that excited electronic states are involved in the ablation process. Experiments with a reference material, i.e., polyimide, for which a photothermal ablation mechanism has been suggested, exhibited pronounced differences. These results strongly suggest that, in case of designed polymers which contain photochemically active groups, a photochemical part in the ablation mechanism cannot be neglected. Various potential applications for laser ablation and the special photopolymers were evaluated and it became clear that the potential of laser ablation and specially designed material is in the field of microstructuring. Laser ablation can be used to fabricate three-dimensional elements, e.g., microoptical elements.Keywords Laser ablation · Ablation mechanism · Photopolymers · Polyimide · Spectroscopy This was not always true, of course. For many years, the laser was viewed as "an answer in search of a question". That is, it was seen as an elegant device, but one with no real useful application outside of fundamental scientific research. In the last two to three decades however, numerous laser applications have moved from the laboratory to the industrial workplace or the commercial market. Lasers are unique energy sources characterized by their spectral purity, spatial and temporal coherence, and high average peak intensity. Each of these characteristics has led to applications that take advantage of these qualities: -Spatial coherence: e.g., remote sensing, range finding and many holographic techniques. -Spectral purity: e.g., atmospheric monitoring based on high-resolution spectroscopies. -and of course the many other applications in communication and storage, e.g., CDs.All of these high-tech applications have come to define everyday life in the late twentieth century. One property of lasers, however, that of high intensity, did not immediately lead to "delicate" applications but rather to those requiring "brute force". That is, the laser was used in applications for removing material or heating. The first realistic applications involved cutting, drilling, and welding, and the laser was little more advanced than a saw, a drill, or a torch. In a humorous vein A.L. Schawlow proposed and demonstrated the first "laser eraser" in 1965 [4], using the different absorptivities of paper and ink to remove the ink without damaging the und...

show abstract

“…In this spectrum, weak bands around 2100 cm −1 are due to Si–H stretching and bands in the 1100–1000 cm −1 region are of Si–O bonds. The 760 cm −1 band is assigned to methyl rocking parallel to the chain axis (Si–CH 3 ) and has the induced dipole moment parallel to the chain axis . Moreover, the band located between 2960–2890 cm −1 is ascribed to the symmetrical stretching mode of the C–H band in the methyl groups, and band at 1260 cm −1 is assigned to the symmetrical bending vibration of the methyl groups (Si–CH 3 bending) .…”

Section: Resultsmentioning

confidence: 99%

Ionic-liquid-mediated poly(dimethylsiloxane)- grafted carbon nanotube fiber prepared by the sol-gel technique for the head space solid-phase microextraction of methyl tert -butyl ether using GC

Vatani

Yazdi

2013

J. Sep. Science

View full text Add to dashboard Cite

A headspace solid-phase microextraction method was developed for the preconcentration and extraction of methyl tert-butyl ether. An ionic-liquid-mediated multiwalled carbon nanotube-poly(dimethylsiloxane) hybrid coating, which was prepared by covalent functionalization of multiwalled carbon nanotubes with hydroxyl-terminated poly(dimethylsiloxane) using the sol-gel technique, was used as solid-phase microextraction adsorbent. This innovative fiber exhibited a highly porous surface structure, high thermal stability (at least 320°C) and long lifespan (over 210 uses). Potential factors affecting the extraction efficiency were optimized. Under the optimum conditions, the method LOD (S/N = 3) was 0.007 ng/mL and the LOQ (S/N = 10) was 0.03 ng/mL. The calibration curve was linear in the range of 0.03-200 ng/mL. The RSDs for one fiber (repeatability, n = 5) at three different concentrations (0.05, 1, and 150 ng/mL) were 5.1, 4.2, and 4.6% and for the fibers obtained from different batches (reproducibility, n = 3) were 6.5, 5.9, and 6.3%, respectively. The developed method was successfully applied to the determination of methyl tert-butyl ether in different real water samples on three consecutive days. The relative recoveries for the spiked samples with 0.05, 1, and 150 ng/mL were between 94-104%.

show abstract

Infrared Spectroscopic Studies on the Molecular Orientation of Vacuum-Deposited Thin Films of Poly(dimethylsilane) and a Linear Oligosilane

Cited by 24 publications

References 35 publications

PDMS–Fluorous Polyoxetane–PDMS Triblock Hybrid Elastomers: Tough and Transparent with Novel Bulk Morphologies

PDMS–Fluorous Polyoxetane–PDMS Triblock Hybrid Elastomers: Tough and Transparent with Novel Bulk Morphologies

Laser Application of Polymers

Ionic-liquid-mediated poly(dimethylsiloxane)- grafted carbon nanotube fiber prepared by the sol-gel technique for the head space solid-phase microextraction of methyl tert -butyl ether using GC

Contact Info

Product

Resources

About