Synthesis and high temperature chemistry of methylsilsesquioxane polymers produced by titanium-catalyzed redistribution of methylhydridooligo- and -polysiloxanes

Laine, Richard M.; Rahn, Jeffrey A.; Youngdahl, Kay A.; Babonneau, Florence; Hoppe, M.; Zhang, Zhi-fan; Harrod, John F.

doi:10.1021/cm00010a028

Cited by 52 publications

(15 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Heating MSQ in air or O 2 above 600 C results primarily in the formation of SiO 2 , which is used for the production of silica glasses. 9 In the case of flame or laser treatment in open air, one can expect more extreme thermal treatment than that delivered by TGA testing; transformation of hydrophobic methyl groups to hydrophilic -OH groups can thus be expected. placed in a water bath and subjected to heating; the hydrophobic islands act as preferred gas nucleation sites-arrows indicate vapor bubbles that grow gradually and detach before this cycle repeats itself over and over.…”

Section: Resultsmentioning

confidence: 99%

Superhydrophobic–superhydrophilic binary micropatterns by localized thermal treatment of polyhedral oligomeric silsesquioxane (POSS)–silica films

et al. 2012

View full text Add to dashboard Cite

Surfaces patterned with alternating (binary) superhydrophobic-superhydrophilic regions can be found naturally, offering a bio-inspired template for efficient fluid collection and management technologies. We describe a simple wet-processing, thermal treatment method to produce such patterns, starting with inherently superhydrophobic polysilsesquioxane-silica composite coatings prepared by spray casting nanoparticle dispersions. Such coatings become superhydrophilic after localized thermal treatment by means of laser irradiation or open-air flame exposure. When laser processed, the films are patternable down to ∼100 μm scales. The dispersions consist of hydrophobic fumed silica (HFS) and methylsilsesquioxane resin, which are dispersed in isopropanol and deposited onto various substrates (glass, quartz, aluminum, copper, and stainless steel). The coatings are characterized by advancing, receding, and sessile contact angle measurements before and after thermal treatment to delineate the effects of HFS filler concentration and thermal treatment on coating wettability. SEM, XPS and TGA measurements reveal the effects of thermal treatment on surface chemistry and texture. The thermally induced wettability shift from superhydrophobic to superhydrophilic is interpreted with the Cassie-Baxter wetting theory. Several micropatterned wettability surfaces demonstrate potential in pool boiling heat transfer enhancement, capillarity-driven liquid transport in open surface-tension-confined channels (e.g., lab-on-a-chip), and select surface coating applications relying on wettability gradients. Advantages of the present approach include the inherent stability and inertness of the organosilane-based coatings, which can be applied on many types of surfaces (glass, metals, etc.) with ease. The present method is also scalable to large areas, thus being attractive for industrial coating applications.

show abstract

Section: Resultsmentioning

confidence: 99%

Superhydrophobic–superhydrophilic binary micropatterns by localized thermal treatment of polyhedral oligomeric silsesquioxane (POSS)–silica films

et al. 2012

View full text Add to dashboard Cite

show abstract

“…It has been reported that between 800 and 1400°C weight loss is limited to Ͻ1.5% and probably reflects the evolution of hydrogen from Si-CH 2 -Si linkages which incorporate into the backbone by redistribution reactions. 10,13,14 XPS analyses, performed at different stages of pyrolysis, showed that all materials are made of silicon (Si2s and Si2p peaks), carbon (1s peak), and oxygen (1s peak), as illustrated in Figure 2 for the pyrolytic residue obtained at 900°C. It is well known that peak positions for XPS data vary somewhat from instrument to instrument.…”

Section: Chemical Change During Pmsq Pyrolysismentioning

confidence: 99%

Pyrolysis of polymethylsilsesquioxane

Shi

et al. 2002

J of Applied Polymer Sci

View full text Add to dashboard Cite

Changes of the composition and structure of various samples of polymethylsilsesquioxane (PMSQ), pyrolyzed at different temperatures under flowing nitrogen, were investigated using thermogravimetric analysis, Raman and Fourier transform infrared spectroscopies, X-ray photoelectron spectroscopy, elemental analysis, scanning electron microscopy, and transmission electron microscopy. The center of the Si2p peak could be used to estimate the extent of the pyrolysis of PMSQ. Two temperature domains correspond to important changes in the chemical composition of PMSQ. The former (T p Ͻ 500°C) is related to the conversion from a regular structure to an irregular structure and the latter (T p Ͼ 500°C) is associated with the organic-ceramic conversion. During the latter pyrolysis, flowing of the molten bulk occurred and then a final solid structure was obtained. The main product of PMSQ, pyrolyzed at 900°C, is silica, as well as some amount of silicon oxycarbide and traces of amorphous carbon. Based on the above analysis and observation, a conversion process from polysilsesquioxane to a ceramic is proposed.

show abstract

“…In addition, when a polymeric starting material contains potentially reactive bonds constituting its polymer chain, undesired side reactions can result. For the present case with PMHS, Laine et al48 and Graczyk and Harrod49 reported that Cp 2 TiMe 2 and other titanium complexes catalyze redistribution reaction of PMHS forming methylsilsesquioxane polymers. Also, Chauhan et al50 communicated that treatment of copper salts with PMHS afforded copper nanoparticles.…”

Section: Resultsmentioning

confidence: 59%

Exhaustive and partial alkoxylation of polymethylhydrosiloxane by copper‐catalyzed dehydrocoupling with alcohols: Synthesis, crosslinking behavior, and thermal properties of the products

Iinuma

Reddy

Hayashi

et al. 2011

J. Polym. Sci. A Polym. Chem.

View full text Add to dashboard Cite

Polymethylhydrosiloxane (PMHS) reacts with aliphatic and aromatic alcohols at room temperature in the presence of [CuH(PPh 3 )] 6 complex catalyst to give poly[(methyl) (alkoxy)siloxane]s in high yields. Reactivity of alcohols decreases in the order of p-methoxyphenol > p-cresol > phenol > benzyl alcohol > allyl alcohol > ethanol > isopropanol > tert-butyl alcohol. Partially p-cresylated polymers, which still retain unreacted SiAH bonds, react further with ethylene glycol or water to form cross-linked polymers, which, depending on the extent of cross linking, gelate during the cross-linking process. Propargyl alcohol reacts with PMHS very rapidly to give exhaustively and partially propargyloxylated PMHS. Resulting polymers, upon heating, undergo crosslinking. Partially propargyloxylated polymers display high thermal stability [T d5 (temperature of 5% weight loss) > 500 C] as compared with starting PMHS (243 C) and exhaustively propargyloxylated one (414 C).Additional Supporting Information can be viewed in the online issue of this article.

show abstract

Synthesis and high temperature chemistry of methylsilsesquioxane polymers produced by titanium-catalyzed redistribution of methylhydridooligo- and -polysiloxanes

Cited by 52 publications

References 2 publications

Superhydrophobic–superhydrophilic binary micropatterns by localized thermal treatment of polyhedral oligomeric silsesquioxane (POSS)–silica films

Superhydrophobic–superhydrophilic binary micropatterns by localized thermal treatment of polyhedral oligomeric silsesquioxane (POSS)–silica films

Pyrolysis of polymethylsilsesquioxane

Exhaustive and partial alkoxylation of polymethylhydrosiloxane by copper‐catalyzed dehydrocoupling with alcohols: Synthesis, crosslinking behavior, and thermal properties of the products

Contact Info

Product

Resources

About