Sandia Corporation

Sandia National Laboratories

Kamyar Rahimian

Douglas A Loy

Blake A Simmons

David R Wheeler

Chad Staiger

James R McElhanon

Gregory M Jamison

Timothy M Long

Thomas Zifer

Shawn Matthew Dirk

Roger D Rasberry

A polymeric matrix material exhibits low loss at optical frequencies and facilitates the fabrication of all-dielectric metamaterials. The low-loss polymeric matrix material can be synthesized by providing an unsaturated polymer, comprising double or triple bonds; partially hydrogenating the unsaturated polymer; depositing a film of the partially hydrogenated polymer and a crosslinker on a substrate; and photopatterning the film by exposing the film to ultraviolet light through a patterning mask, thereby cross-linking at least some of the remaining unsaturated groups of the partially hydrogenated polymer in the exposed portions.

Polymeric matrix materials for infrared metamaterials

Two new surfactant molecules are reported which contain thermally labile Diels-Alder adducts connecting the polar and non-polar sections of each molecule. The two surfactants possess identical non-polar dodecyl tail segments but exhibit different polar headgroups. The surfactants become soluble in water when anionic salts are formed through the deprotonation of the surfactant headgroups by the addition of potassium hydroxide. When either surfactant is exposed to temperature above about 60&#xb0; C., the retro Diels-Alder reaction occurs, yielding hydrophilic and hydrophobic fragments or the aqueous solutions of the surfactants subsequently exhibit loss of all surface-active behavior.

Thermally cleavable surfactants

The present invention describes surfactants of formula (I), wherein R, R, and m are defined herein, processes for their preparation, and methods for their decomposition.

Method for preparing thermally cleavable surfactants without deprotonation

A class of surfactant molecules whose structure includes regularly spaced unsaturation in the tail group and thus, can be readily decomposed by ring-closing metathesis, and particularly by the action of a transition metal catalyst, to form small molecule products. These small molecules are designed to have increased volatility and/or enhanced solubility as compared to the original surfactant molecule and are thus easily removed by solvent extraction or vacuum extraction at low temperature. By producing easily removable decomposition products, the surfactant molecules become particularly desirable as template structures for preparing meso- and microstructural materials with tailored properties.

Metathesis depolymerizable surfactants

Thermally cleavable surfactants without deprotonation

Two new surfactant molecules are reported which contain thermally labile Diels-Alder adducts connecting the polar and non-polar sections of each molecule. The two surfactants possess identical non-polar dodecyl tail segments but exhibit different polar headgroups. The surfactants become soluble in water when anionic salts are formed through the deprotonation of the surfactant headgroups by the addition of potassium hydroxide. When either surfactant is exposed to temperature above about 60&#xb0; C., the retro Diels-Alder reaction occurs, yielding hydrophilic and hydrophobic fragments and the aqueous solutions of the surfactants subsequently exhibit loss of all surface-active behavior.

A method for disproportionation of an oligohydridosiloxane to produce a polysilsesquioxane compound and an organohydridosilane compound when contacted with a basic catalyst. The basic catalyst can be a tetraalkylammonium hydroxide, an alkali metal hydroxide, and an alkali earth hydroxide. These basic catalysts are generally dissolved in an organic solvent for delivery. The hydroxide catalysts are attractive because many readily decompose by heating above 150&deg; C., thus being easily removed from the final materials. The oligohydridosiloxane is contacted with the basic catalyst under conditions effective to catalytically convert the oligohydridosiloxane into a polysilsesquioxane compound and an organohydridosilane compound. The reaction can occur in either an inert or oxidative atmosphere and can occur without heating, at room temperature. Both polysilsesquioxane foams and gels of the formula (RSiO,),can be produced.

Method for making polysilsesquioxanes and organohydridosilanes

Cross-linked polymers formed by ring-opening polymerization of a precursor monomer of the general formula R&lsqb;CH,CH(Si(CH,),),O&rsqb;,, where R is a phenyl group or an alkyl group having at least two carbon atoms. A cross-linked polymer is synthesized by mixing the monomer with a co-monomer of the general formula CH,CHR,(SiMe,),O in the presence of an anionic base to form a cross-linked polymer of recurring units of the general formula R(Me,SiOCH,CHSiMe,),&lsqb;CH,CHR,(SiMe,),O&rsqb;,, where R,is hydrogen, phenyl, ethyl, propyl or butyl. If the precursor monomer is a liquid, the polymer can be directly synthesized in the presence of an anionic base to a cross-linked polymer containing recurring units of the general formula R(Me,SiOCH,CHSiMe,),. The polymers have approximately less than 1% porosity and are thermally stable at temperatures up to approximately 500&deg; C. The conversion to the cross-linked polymer occurs by ring opening polymerization and results in shrinkage of less than approximately 5% by volume.

Growing community of inventors

Albuquerque, NM, United States of America

Kamyar Rahimian