Title of Invention

"A METHOD OF MODIFYING THE SURFACE PROPERTIES OF A SUBSTRATE AND A SUBSTRATE"

Abstract

A process of modifying t solid's surface, comprising a first step of depositing hydragenaed armophous silicon on the surface by thermal decomposition at an davated temperature of silicon hydride gas to form silona spdieals which redom- bine to cont the surface with hydrogensted srmop-hous silicon. A second step of surfce funtionaliza-non of the hydrogenated aimophous silicon in the presence of a binding agent Including hydrosilyla-tion, disproportlonation and mdical quenching.

Full Text

The present invention relates to a method of modifying the surface properties of a substrate and a substrate. Related Applications This application claims priority to Prc visional Application No. 60/122,990 entitled Surface Functionalization of Solid Supports Through the Thermal Decomposition and Hydrocilylation of Silanor filed 4/1/99 by David Abbott Smith. Field of (he Invention This invention relates to a process for depositing a layer of hydrogenated amorphous silicon (a-SiH) to a substrate, followed by a reaction of an unsaiurated reagent to modify the (surface properties including, but not limited to, inactivity to acidic, basic, and neutral compounds, resistivity to attack from caustic environments, and wettability toward other compounds. Radical quenching processes may also be usiid to complete the surface modification. Background of Prior Art The current invention has been developed to overcome the inherent undesirable molecular activities of metel (ferrous and non- ferrous), glass, and ceramic surfaces which c:an cause the following: (a) chemisorption of other molecules, (b) reversible and irreversible physisorption of other molecules, (c) catalytic reactivity with other molecules, (d) allow attack from foreign species, resulting in a molecular breakdown of the surface, or (e) any combination of (a)-(dj. The prior art shows the use of silan.es or silicon hydrides to modify surfaces. The present invention utilizes the formation of a hydrogenated amorphous silicon coating on a surface through the decomposition ofsilanes or silicon hydrides, followed by a secondary process of surface functionalzation with a reagent containing at least one unsaturated hydrocarbon group (e.2, -CH=CH2 or -C=CH), Additional elimination of residual surface defects can be achieved through reagents capable of thermal dispropon ionation and'or radical quenching. It is known in the prior art to form a silicon hydride surface through a) halogenation of surface silanol moieties; followed by reduction, and b) reacting surface silanol moieties with reagents such as trihydroxyhydridosilane via sol-gel type methods. This invention utitizes the thermal dccompoaition. and deposition of silanes or silicon hydrides to impart an hydrogenated amorphous silicon layer on the substrate. The substrate does not require the presence of surface siianol moieties for the deposition to occur, thersby allowing a wide range of substrate types, such as metals, glasses and ceramics. It is known in the prior art to funaionalize a silicon-hydride surface with unsaturated hydrocarbon reagents in the presence of a metal catalyst. The complete removal of this catalyst from the treated system is often difficult and trace presence of the ca;.ulyst c;m reintroducc undesirable surface activity. The present invsnuon does not employ an additional metaJ catalyst. Instead, the process is driven fay heat. Without the use of a metal catalyst, the final product is void of additional residual catalyst activity and does not require removal of it. Jt is known in the prior art to enhance the silicon hydride surface concentration by treatment of silicon metaloio with hydrofluoric acid. This invention utilizes the inhere formation of silicon hydride surface via the thermal decomposition of silanss. Further treatment to enhance siiicon hydride surface moieties are not necessary. Summary of the Invention The present invention provides a modifying the surface properties of a substrate by depositing a layer of hydrogenated amorphous silicon on the surface of the substrate and then functionalizing the coated substrate by exposing the substrate to a binding reagent having at least one unsaturated hydrocarbon group. Using the menhod of the: present invention, surface properties such as inactivity to acidic, basic and neutral compounds, resistivity to attack from caustic environments, and wettability toward other compounds is modified. The method can be used on ferrous and non-ferrous metal, glass anc cerumic surfaces The method of modifying the surface progenies of a substrate of the present invention comprises the steps of depositing a coating of hydruydialed ainoiphous siliuun on the surface t'f trie substrate, and then functionaiizing the coated substrate by exposing the substrate to a binding reagent having at least one unsaturated hydrocarbon group under elevated temperature for a predetermined length of time. The hydrogenated amorphous silicon coating is deposited by exposing the substrate to silicon hydride gas under elevated temperature for a predetermined length of time. The preaaure, tsmperature wad time of exposure to hydrogenated amomhous silicon is controlled to prevent formation of hydrogenated amorphous silicon dust. The substrate is initially cleaned by heating it at a temperature between about 100° and about 600° C for a time psriod ranging from a few minutes to about 15 hours before exposing the substrate to hydrogenafed amorphous silicon. In an embodiment, the substrate is cleaned at about 120° C for about 1 hour. In a preferred embodiment, the substrate is isolated in an inert atmosphere before exposing the substrate to silicon hydride gas. The substrate is exposed to silicon hydride gas j.t a pressure between about 0.01 p.s.i.a. to about 200 p.s.i.g. and a terr perature between about 200° and 600° C tor about 10 minutes to about 24 hours. More preferably, the substrate is exposed to silicon hydride gas at a pressure between about 1.0 p.s.i.a. and about 100 p.s.i.a. f,nd a temperature between about 300° and 600° C for about 30 mirutas to about 6 hours. Better yet, the substrate is exposed to silicon hydride gas at a temperature between about 350° and about 400° C for about 4 hours. Thepreasure of the silicon hydride gas is preferably between about 2.3 p.s.i.a. and about 95 p.s.i.a. In an embodiment of the invention, the sutstrete is exposed to silicon nydnde gas at a temperature ot about 400° C and pressure of about 2.5 p.s.i.a. In another embodiment, the substrate is expowed to silicon hydrida gas nt ;\ lemp«rnhtrfi nf about 40° C nnd a pressure of about 44 p.o.i.g,, and than the tomporature io neiaad to about 3S5° C. The substrate is also preferably isolated in iin inert atmosphere before functionalizing the coated substrate with a .substitute unsaturated hydrocarbon. The substrate (a function* liztd v. o. press me between about 0.0 i p.s.i.a. to about 200 p.s.i.a. aud a temperature between about 200° and 500° C for about 30 minutes to about 14 hours. More preferably, the substrate is exposed to the binding reagent at a temperature less than about 100°C, and then th« t»np«rature ie inoreaacd to between 250° and 500° C while the pressure is maintained less than about 100 p.s.i.a. The method may includejbe step of quenching residual silicon radicals in the hydrogenated amorphous silicon coating either before or after the hydrosilylation step. In this step, the substrate is isolated in an inert atmosphere before quenching the residual silicon radicals in the silicon coating. Preferably, the substrate is quenched exposing the substrate to organosilanes, amines, or known radical scavengers under ejevated pressure and temperature for a predetermined length of time to cause thermal dispioponionation. The suuslialc iij quenched at a temperature between about 250° and 500° C for aoout 30 minutes to about 24 hours. The method may also include the siep of exposing the substrate to oxygen prior to or contemporaneous with u\e hydrDsfJylation step ln one embodiment, up to about 3% by weight oxygen is mixed with said binding reagent. In another embodiment, the substrate is exposed to 100% oxygen or mixtures of oxygen in other gases at temperature about 100° to 450° C fora few seconds to about 1 hour prior to hydrosilylatinfi. More preferably, the substrate is exposed to zero air at about 25 p.s.i.g. and about 325° C for about 1 minute. Brief Descrition of the ACCOMPANYING Drawings Fig. 1 is a schematic illustration of a substrate treated in accordance with the present invention. Description of Preferred Embodiments pf tin Inventjpn The invention disclosed herein comprises a primary treatment step, followed by further steps of hydrog enated amorphous silicon functionalization. These additional processes ir elude the reaction types of hydrosilylation^ disproportionation and radicjJ quenching. The process of the present invention utilises elevated temperatures and inert atmospheres. The substrz.te or surface to be treated must be isolated in a system which permits the flow of gases via pressure and vacuum, and within a heat source, such as an oven. For example, the surface to be treated could b* within a «teel vessd with tubing connections to allow gas flows. Depending o;n the cleanliness of Ihe substrate, it may be cleaned initially by heating it under air atmosphere at a temperature betweeen anout 100° C fo a time period ranging from a few minutes to about 5 hours, better yet about 0.5 to about 15 hours. In a preferred embociment, the substrate is cleaned at about J20°C for about! hour. After thi:) oxidation step, the atmosphere within the vessel is made inert by flus.iing the vessel with an inert gas and applying a vacuum. The substrate rrny also b« cleaned with an appropriate liquid or supercritical fluid solvent. After the substrate is cleaned arid the vessel is evacuated, the substrate is exposed to silicon hydride gas (SiH4, Si nH2n-2) under eletvated pressure and temperature for a predetermined period of time. Silicon hydride 0as ia introduced into the vess si at fl nresKiire between about 0.01 pounds per square inch absolute (piria) and about 200 pounds per square inch gauge pressure ipsig). The silicon gas may be introduced into the vesse! at low pressure and an elevated temperature, such as 2.5 p.s.i.a. and 400°C Alternatively, the silicon gas may be introduced at a moderate pressure and low tern Demure, such as 44 p.S.i.g. and 40"C, and then lamped lu a liigli Iciupcmiujc auL.h as 353nC. In either case, the substrate should be exposed 10 silicon hydride gas at an elevated temperature from about 200" to abcut 600° C, better yet between about 300" and 600°C, and preferably from about 3 50° to 400°C for an extended period of time, The exposure time of the substratc to silicon nyandc gna may range rrom iv minmoo to 24 hours, preferably between about 30 minutes and about 6 hours, and typically about 4 houra. A preferred temperature ie 350U|U-'1000C tor 1 hours. In the presence of heat, the silicon hydride gus thermally dissociates to form si lane radicals which recombine and bind to the substrate surface. The resultant coating is hydrogen a ted amorphous silicon which has Si-Si, Si-H, and Si (radical) moieties on the surface and in the bulk. The time, pressure and temperature of the silicon hydride gas exposure step will vary depending on the ohemicil properties tDf the K. The time, pressure and temperature must be controlled to flvoid undesirable by-products of the axposu 'e alcp. For example, if the pressure and temperature are too high, or if tiie substrate is exposed to silicon gas for too long a time period, undesirable hydrogenatcd amorphous silicon dust may form on the substrate. Mijiiunzaliuii of dust formation is unique to the vessel type, substrate type and substrate surface area. If the pressure or temperature is too low, or if the exposure fltep is too short, no silicon coating will form, or cm inhomogeneous contingof hydrogenated amorphous silicon w:ll form. Optimization of the silane deposition process (dust minimization and uniform film deposition) is achieved through prftssnr-. temperature and time variations fof each unique process. After t)ic hydrogenated amorphous silicon ilcpusk'ii piuucsa Ja complete, the system is purged with an inert gas to remove silane moieties not bound to the substrate surface. Alter the inert gas purge, the vessel in evacuated. A binding agent is then introduced into the vessel under elevated temperature and pressure. With heat as a driving force, the reagent reacts with and binds to the hydrogenated amorphous silicon surface via silicon hydride moieties. The reagent used determines the physical properties displayed by the nexvjy functionalized surface. Surface properties of the substrate can be tailored for a wide variety of functions depending on the reagent used in the process. The binding reagent must have at least one unsaturated hydrocarbon group (i,e, -CH-CH3 or-OCH). The reagent may be further comprised of hydrocarbons, substituted hydrocarbons, carbon y is, carboxyis, esters, amines, amides, sulfonk: acids, and epoxides. A preferred binding reagent is ethy lene. The binding agent is introduced into the vessel at a, pressure range of about U.O I to about 200 p.s.i.a. The binding agent is preferably infrocuced into the. vessel at a temperature less than about 100° C. For example, in one embodiment, the binding agent is introduced into the vessel at i:ess than about 100° C and about 25 p.s.i.g. After the binding agent is introduced into the vessel, the temperature of the reagent is raised to about 200* to about 500° C, better yet up to about 250° to about 500° C. Preferably, the increased reaction pressure is less than about 200 p.s.i.a., better yi:t jess than about 100 p.s.i.a. For example, in one embodiment, the reaction temperature is about 360° C. The reaction time varies from 30 minutes to '24 hours, but typically lasts about 4 hours. The presence of oxygen mixed at low levels (0-5%) v/ifh ethylene, or an oxygenatjon step (100% oxygen or mixtures of oxygen in other gases) prior to hydros!lylating the substrata has also shown to assist the deactivation qualities of the hydrogenzited amorphous silicon surface. If the process employs an oxygen/ethyl sne gas mixture, a typical ratio is 2.5% zero air (a nitrogen/oxygen mix) in ethylene. If an oxygenation step is used prior to hydrosilylation (ethylene bonding), the process includes flushing the surface with oxygeu/oxygen-containing mixtures at high temperatures, about 100 1:0 abou! 430° C, for a period of time ranging from a few seconds to about 1 hour. A typical preoxygcnation step involves flushing the surface with zero air at about 25p.s-i.g. for about 1 minute at 325°C. Surface defects in the hydrogenated amorphous silicon surface, also known as "dangling bonds" or silicon radical:!, may create undesirable secondary reactions between the surface and other compounds if left untreated. Quenching of residual radicals is achieved by thermal disproportionation of organosilanes (e.g., SiR1,R2,R3R4 amines (e.g, NR1R2R3.) or known radial scavengers (e.g. BHT, hydroquinone, reducing agents, thiols), where R^H, alky!, alkenyl, aryl, halogen, omine, organosijyl). One example is phonylmethylyingloilane. This process may be omployod psier to or subsequently after reacting the hydrogenated amorphous silicon with a terminally unsaturated hydrocarbon. Ranges of reaction time and temperature are 2500C-500°C and 30 minutes lo 24 hours. Examples of applications for this invention are, but not limited to, the passivation and/or modification of solid supports, transfer lines, inlet systems, detector systems, columns, etc. used in chromaiographic analyses, and the passivation and enhancement of corrosive resistivity of metal surfaces. The following examples are provided to further illustrate the invention. Example 1 Borosiiicate inlet liners are used in gas chomatography inctrumento an the area of sample introduction and transfer on to a gaa chomatography column. Since raw borosilicate glat;s has an active surface and is adsorptive to many compounds, it is typically deactivated through a silanizfttion process. Standard silanizationu give a relatively inert surface, but do not allow for universal inertness to acidic nnd basic compounds (e.g. carbowylic acids and amines) Some liners work for acidjc compounds and fewer types work well for basic compounds. The current invention provides a surface whic.1 will prevent the adsorption of acidic and basic compounds to the inlet liner surface. Borosilicatc inlet liners are packed into a stainless steel vessel which is sealed and connected to inlet and outlst tubing. The tubing is passed through the ceiling of an oven and connected to two separate mmifolds through which goacs and vacuum can be- applied to the vessel via valve syscems. WJch atmospheric pressure air In the vessel, the vessel temperature is increased to 120'C and held for 1 hour. At the end of 1 hour, the vessel environment is made inert by a nitrogen purge and applied vacuum. The vessel is heated to 400°C After evacuation of the vessel, 100% silanegas (SiHj) is introduced at 1.5 psia. The temperature is held at 400°C for 4 hours during which a hydrogenatcd amorphous silicon layer is deposited on the borosilicate glass, The temperature is then decreased to 3 nitrogen and the vessel environment is made inert by nitrogen purge and applied vacuum. If radical quenching is necessary, phenyimethylvinylsilane vapor is introduced at 300°C and 16 psia, and that temperature is held for 4 hours. Unreacted ptenylrnethylvinylsilane is then purged out with nitrogen as the oven is coded down to room temperature. Example 2 Unctoated fused silica capillary columns are used in gas chromatography instruments as an inert transfer line from the inlet liner to the coated fused silica capillary analytical column. Since; raw fused silica glass has an active surface and is adsorpiive to many compounds, it iu typically deactivated through a silnnizatior process. Standard silanizations give a relatively inert surface, but do not allow for universal inertness to acidic and base compounds fe.g., carboxylic acids and amines). 3ume deactivated, fused silica columns work well for acidic compounds and fewer type's work well for bacis compounds.. Also, typical deactivations are not resistive to repetitive subjection to oauotic cnvironirionto- The current invention povieles a surface on a fused silica capillary which will prevent the adsorption of acidic and basic compounds, as we!! as resist degradation by caustic environments. Fused silica capillary tubing is coiled and tied in 30m lengths, ond itc and are passed through the ceiling ofan over and aomiaated to two separate manifolds through which gases and vacuum can be applied via valve systems. The inherent internal oleanlinsss of fused siilica tubing does not require an oxidativc cleaning stej). The inside uf the tubing is made inert by a nitrogen purge and applied vacuum. After ovacualion of the tubing, 10000 oilane, goo (Dill4) inboda at60 psig. The temperature is ramped to 350°C and held for 4 hours during which a hydrogenated amorphous silicon layer is deposited on the inside of Ihe capillary. The temperature is then decreased to 40°C followed by a nitrogen purge of the remaining unreacted silane ga.1?. The tubing is again made inert by nitrogen purge and applied vacuum. After evacuation of the tubing, ethylene gas is introduced and equilibrated throughout at 25 psig, and the temperature i.5 ramped 360°C and held for 4 hours, Ethylene then bonds via (he Si-fc surface moieties to from an Si-ethyl surface. The temperature is then decreased to 40°C and unreacted ethylene is purged out with nitrogen. The tubing; is made inert by nitrogen purge and applied vacuum ff radical quenching is necessary, phenylmethylvinylsilane vapor is introduced at 16 psia followed by a thermal treatment at 360°C for 4 hours. Unnsacied phenylmethylvinylsilane is then purged out with nitrogen as the oven is cooled down to room temperature. 3 It is desirable to use steeJ vessels to stor; low levels of sulfur compounds such as hydrogen sulflde and mercupuins. Steel is highly adsorptive to these compounds, and therefore is: not considered an appropriate storage media for low parts per bill: on concentrations. The current invention provides a surface which will prevent the adsorption of low-level sulfur compounds to the steel vessel surface. Steel vessels are packed in to a large stahless steel containment vessel which is sealed and connected to inlet and outlet tubing. The tubing is passed through the ceiling of an oven and sonnected to two separate manifolds through which gases and vacuum can be applied to the vessel via valve systems. With atmospheric pressure air in the vessel, the vessel temperature is increased to 12C°C and held for 1 hour. At the end of 1 hour, the vessel environment is made inert by a nitrogen purge and applied vacuum. The vessel ia heated to 400°C. After evacuation of the vessel, 100% silane gas (S HJ is introduced at 2.5 psia. The temperature is held at 400°C for 4 hours during which a hydrogenated amorphous silicon layer is deposited. The temperature is then decreased to 360°C followed by a nitrogen purge of the remaining unreacted silane gas. The containment vessel environmeni: is again made inert by nitrogen purge and applied vac mm. After evacuation at 360°C, ethylene gas is introduced at 25 psig and 360°C is held for 4 hours Ethylene then bonds via the Si-iH surface moieties to form an Si-ethyl surface. Unreacted ethyJene is th«:n purged out with nitrogen and the containment vessel environment is made inert by nitrogen purge and applied vacuum. If radical quenching is necessary, phenylmethylvinylsilane vapor is introduced ai 360°C and 16 psig, and that temperature is hdd for 4 hours. Unreactec phenylmethylvinylsilane is then purged out with nitrogen as the oven is cooled down to room temperature. .Example 4 Borosilicate inlet liners are used in gas c iromatography instruments as the area of sample introduction and 'transfer on to a gas chromatography column. Since raw borosilicato glass has an active surface and is adaorptive to many compounds, it is typically deactivated through a silanization process. Standard silaniztions give a relatively inert surface, but can cause the chemical breakdown of unstable compounds and do not allow for universal inertnsss to acidic and basic compounds (e.g, carboxylic acids and amines). Some liners work well for acidic compounds and fewer types work well for basic compounds. The current invention provides a surface which will prevent the ndsorption of ae/dic and basic compounds to (he inlet liner surface. Borosilicate inlet liners are packed intc a stainless steel vessel which is sealed and connected to inlet and outlet i.ubing. The tubing is passed through the ceiling of an oven and connected to two separate manifolds through which gases and vacuum cg,n be applied to the vessel via valve systems. Depending on the ci'eanh'ness of the liners, an oxidated cleaning step can be employed. With atmospheric pressure air in the vessel, the vessel teuipeiatuie is inueased to 120°C and held for 1 hour. At the end of 1 hour, the vessel environment is made inert by a nitrogen pitrge and applied vacuum. The vessei is heated to 400°C. After evacuation of the vessel, 100% si Jane gas (SiH^) is introduced at 2.5 psia. The temperature is held at 400°C for ^ hours during which a hydrogenated amorphous silicon layer is deposited on the borosiiicate glass, A nitrogen purge is introduced, followed by a temperature decrease to Jess than about 100°C The vessel environment is again made inert by nitrogen purge and applied vacuum. After evacuation of the vessel, ethylene gas with 2 .5% zero air is intioduced at 8 p.s.i.g. The temperature js men increased to almost 355° C and is held for about 4 hours. Ethylene then bonds via the Si-H surface moieties to form an Si-ethyl surface. After cooling, unreacted ethylene ;s then purged out with nitrogen and the vessel environment is made iner by nitrogen purge and applied vacuum. If radical quenching is necessary, phenylmethylvinylsilane vapor is introduced at 360°C and 16 psia, and that temperature is held for 4 hours. Unreaicted phenylmethylvinylsUane is then purged out with nitrogen as the oven is cooled down to room temperature. Example 5 Uncoated fused sijica capillary cojurrns are used in gas chromatography instruments as an inert transfer line from the iniet Jiner to the coated fused silica capillary analytical column. Since raw fused silica glass has an active surface and is adsorptive to many compounds, it is typically deactivated through a si (tin izati en process. Standard silanizations give a relatively inert surface, but can still cause the chemical breakdown of certain active component and do not allow for universal inertness to acidic and base compounds (e.g,t carboxylic acids and amines). Deactivated fused silica column;: do not always have a desired level of inertness, and although some ceactivated fused silica columns work well for aoidic compounds, few types work well for basic compounds. Also, typical deactivations are no: resistive to repetitive subjection to caustic environments. The current invention provides a surface on a fused silica capillary which will prevent the adsorption of acidic and basic compounds, as well as resist degradation by caustic environments. Fused silica capillary tubing is coiled and tied in 120m lengths, and its end are passed through the Ceiling of an oven and connected to two separate manifolds through which gases anc vacuum can be applied via valve systems. The inherent internal cleanliness of fused silica tubing does not require an oxidative cleaning step. The inside, of the tubing is made inert by a nitrogen purge and app ied vacuum. After evacuation of the tubing, 100% silane gas (SiH4) is introduced at 60 psig. The temperature is ramped to about 350°C and held for 4 hours during which a hydrogenated amorphous silicon layer is deposited on the inside of the capillary. The remaining si Jane gas is purged out with nitrogen followed by decreasing the oven temperature to less than about J00° C. The tubing is again made inert by nitrogen purge and applied vacuum. After evacuation of the tubing, a mixture of 2.5% air in ethylene gas is introduced and equilibrated throughout at 30 p.s.i.g.. and the temperature is ramped to about 355a C and held for about 4 hours. Ethylene then bonds via the Si-H surface moie :ies to form an Si-ethyl surface. The temperature is then decreased to less than about 100° C and unreacted ethylene is purged out with nitro.jen. The tubing is made inert by nitrogen purge and applied vacuum. IF radical quenching is necessary, phenylmethylvinylsilane vapor is introduced at 16 p.s.i.a. followed by a thermal treatment at 360°C for 4 hours. Unreacted phenylmethylvinylsilane is then purged out with nitrogen as the oven is cooled down to room temperature. Example 6 It is desirable to use steel vessels to store ow levels of sulfur compounds such as hydrogen sulfide and mercaptann. Steel is highly adsorptive to these compounds, and therefore is not considered an appropriate storage media for low parts per billion concentrations. The current invention provides a surface which will pievent the adsorption of low-level sulfur compounds to the steel vessel surface Steel vessels are packed into a large stainless steel containment vessel which is sealed and connected to inlet and outlet tubing. The tubing is passed through the ceiling of an oven anc connected to two separate manifolds through which gases and vacuum can be applied to the vessel via valve systems, if an oxidarivc cleaning step is required, vessel icrupcruiure Is increased ro I2U-L' with atmospheric pressure air in the vessel and held for 1 hour. At the end of J hour, the vessel environment is made inert by a nitrogen purge and applied vacuum. The vessel is heated to 400°C. After evacuation oi the: vessel, 100% silane. gas (SiHJ is introduced at 2.5 p.s.i.a. The temperature is held at 400°C for 4 hours during which a hydrogenated amorphous silicon layer is deposited. Remaining silane gas is purged out with nitrogen followed by a reduction in temperature to less than about 100° C. The containment vessel environment is again made inert by nitrogen purge and applied vacuum. After evacuation at less than about I00°C, etnylene gas is introduced at 25 p.s.i.g. and the lemperature iu ramped to about 360°C is held for 4 hours. EthyJene then bonds via the Si-H surface moieties to form an Si-ethyl surface. After cooling to less than about 100° C, unreacted ethylene is then purged out with nitrogen and the containment vessel environment is made inert by nitrogen purge and applied vacuum. If radical quenching is necessaiy, phenylmethylvinylsilane vapor is introduced at 3i50°C and 16 psig, and that temperature is held for about 4 hours. Unreacted phenylmethyfvinylsilane is then purged out with nitrogen as ths oven is cooled down to room temperature. WE CLAIM: 1. A method of modifying the surface properties of a substrate, comprising the steps of depositing a coating of hydrogenated amorphous silicon on the surface of the substrate by exposing the substrate to silicon hydride gas at a pressure between 0.01 p.s.i.a. to 200 p.s.i.g. and at a temperature between 200°C and 600°C for 10 minutes to 24 hours, optionally first exposing the substrate to silicon hydride gas at a temperature of 40°C and at a pressure of 44 p.s.i.g. and then increasing the temperature to 355°C, functionalizing the coated substrate through hydrosilylation by exposing the substrate to a binding reagent having at least one unsaturated hydrocarbon group as herein described by exposing of the substrate to the binding reagent having at least one unsaturated hydrocarbon group at a pressure between 0.01 p.s.i.a. to 200 p.s.i.a. and a temperature between 200°C and 500°C for 30 minutes to 24 hours, 2. The method as claimed in claim 1 comprising optional step of isolating the substrate in an inert atmosphere before coating hydrogenated amorphous silicon and before the step of functionalization through hydrosilylation. 3. The method as claimed in claim Icomprising optional cleaning the substrate by heating it at a temperature between 100°C and 600°C for a time period ranging from a few minutes to 15 hours before the step of depositing a coating of hydrogenated amorphous silicon on the surface of the substrate. 4. The method as claimed in claim 1 comprising optionally, isolating the substrate in an inert atmosphere and quenching residual silicon radicals in the hydrogenated amorphous silicon coating at a temperature between 250°C and 500°C for 30 minutes to 24 hours either before or after functionalizing the coated surface, said quenching comprises exposing the substrate to organosilanes, amines, or known radical scavengers at a temperature between 250°C and 500°C for 30 minutes to 24 hours to cause thermal disproportionation. 5. The method as claimed in claim 1 comprising optionally exposing the substrate to oxygen prior to or contemporaneous with functionalizing the substrate, or optionally mixing up to 5 % by weight oxygen with said binding reagent, or optionally exposing the substrate to 100 % oxygen or mixtures of oxygen in other gases at a temperature of 100°C to 450°C for a few seconds to 1 hour prior to hydrosilyating, 6. The method as claimed in claim 1, including the step of setting the pressure, temperature and time of the step of depositing a coating of hydrogenated amorphous silicon on the surface of the substrate in a manner to prevent the formation of hydrogenated amorphous silicon dust. 7. The method as claimed in claims 1 or 2, the optionally cleaning of the substrate being at 120°C for 1 hour. 8. The method as claimed in claim 1 wherein depositing a coating of hydrogenated amorphous silicon on the surface of the substrate preferably at a pressure between 1.0 p.s.i.a. and 100 p.s.i.a. and at a temperature between 300°C and 600°C for 30 minutes to 6 hours, and more preferably at a pressure between 2.3 p.s.i.a. and 95 p.s.i.a. and at a temperature between 350°C and 400°C, and most preferably at a pressure of 2.5 p.s.i.a. and at a temperature of 400°C. 9. The method as claimed in claim 1 wherein functionalizing the coated substrate by initially exposing the substrate to the binding reagent at a temperature less than 100°C and then increasing the temperature to between 250°C and 500°C and maintaining the pressure less than 100 p.s.i.a. 10. A substrate having modified surface properties produced by the method as claimed in claim 1.

Documents:

in-pct-2001-00790-del-abstract.pdf

in-pct-2001-00790-del-claims.pdf

in-pct-2001-00790-del-complete specification (granted).pdf

IN-PCT-2001-00790-DEL-Correspondence-Others.pdf

in-pct-2001-00790-del-correspondence-po.pdf

in-pct-2001-00790-del-description (complete).pdf

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in-pct-2001-00790-del-pct-210.pdf

in-pct-2001-00790-del-pct-304.pdf

in-pct-2001-00790-del-pct-401.pdf

in-pct-2001-00790-del-pct-409.pdf

IN-PCT-2001-00790-DEL-Petition-137.pdf

in-pct-2001-00790-del-petition-138.pdf