Manufacturing of hybrid organic-inorganic silica aerogels

Abstract

The present invention relates to the production of aerogels or xerogels. Particularly, the invention relates to a method for the manufacturing of a hybrid organic-inorganic silica aerogel or xerogel with good hydrophobic and thermal insulation properties, comprising heating a silica or organosilica gel which comprises an organic compound to at least 200 °C, whereby the organic compound is at least partially pyrolyzed, and drying the gel. The invention further relates to so-obtained aerogels or xerogels.

Description

[0001] MANUFACTURING OF HYBRID ORGANIC-INORGANIC SILICA AEROGELS

[0002] TECHNICAL FIELD

[0003] The present invention relates to the production of aerogels or xerogels. Particularly, the invention relates to a method for the manufacturing of a hybrid organic-inorganic silica aerogel or xerogel with good hydrophobic and thermal insulation properties.

[0004] BACKGROUND

[0005] Silica aerogels and xerogels are a valuable class of porous materials used for thermal insulation because of their low thermal conductivity. More specifically, because of their low density, large surface area and sub-nanometer pore size, heat transport through the aerogel or xerogel open cell structure is low. Commonly, such an open cell structure is obtained by polycondensation of, for instance, alkoxysilanes in the presence of a solvent, followed by drying the produced wet silica gel under supercritical or subcritical conditions to obtain a solid silica aerogel or xerogel. Importantly, collapse of the gel structure during the drying process should be avoided and will depend on the chosen solvent, temperature, and pressure. As such, the chosen drying technology has a significant impact on the final material properties of the aerogel or xerogel.

[0006] A variety of different silica aerogels and xerogels are known and they may be inorganic or an organic-inorganic hybrid material. Especially organic-inorganic hybrid silica aerogels are currently of high interest because they can retain the structure and physical properties of a silica aerogel, while providing other attractive properties such as hydrophobicity. Usually, the organic component is covalently bound to the silica network, by adding organosilicon during the polycondensation process, providing chemical bonding between the organic and inorganic phase.

[0007] Next to hydrophobic properties, heat insulation can be further optimized by integrating opacifiers in the organically modified aerogels. For this purpose, finely dispersed carbon black powders are usually introduced into the silica aerogel during the sol-gel process or by physical mixing with a silica aerogel powder. However, homogenous dispersion is very important for efficient opacification, which is difficult to achieve using carbon black powders due to agglomeration of carbon black particles. In order to avoid these issues, carbonaceous structures can also be formed through pyrolysis of organic groups attached to a modified silica aerogel. Typical pyrolysis conditions include heating the organically modified aerogel usually around 1000 °C in an inert atmosphere (e.g. argon) or in the presence of gaseous organic compounds (e.g. methane). Under these conditions, the aerogel is converted from a transparent to a brown or black (usually) hydrophobic material.

[0008] It is an aim of the present invention to provide alternative and even improved methods for the manufacturing of hybrid organic-inorganic silica aerogels or xerogels, that provide inter alia improved hydrophobicity of the resulting products.

[0009] SUMMARY

[0010] The present invention is at least in part based on the discovery that hybrid organic-inorganic silica aerogels or xerogels can be obtained with good hydrophobic and thermal insulation properties by heating a silica or organosilica gel comprising an organic compound, and drying the gel. The present inventor has discovered that at least partial pyrolysis of the organic compound which takes place during the heating generates hydrophobic and opacified aerogels, even when the organic compound comprised by the gel is hydrophilic. As a result, no (or less) hydrophobizing agents and opacifiers need to be added for high hydrophobicity and good thermal insulation properties. The so-obtained gels can also be stronger than obtained by previously existing methods.

[0011] Advantageously, compared to the prior art, cheaper and more available organic compounds can be used for the production of hydrophobic aerogels or xerogels, not restricted to organosilicon compounds (such as organosilanes). In addition, pyrolysis can be performed at much milder temperatures than previously done on dried aerogels, such as at temperatures up to at most 400 °C, and without the need for an inert atmosphere. Another advantage of the current invention is that the water content does not need to be very precisely controlled during pyrolysis and / or drying to obtain hydrophobized aerogels, thus avoiding tedious solvent exchanges to reduce the water content.

[0012] In view of the inventor’s unexpected findings, an aspect of the invention provides a method for manufacturing a hybrid organic-inorganic silica aerogel or xerogel, comprising heating a silica or organosilica gel which comprises an organic compound to at least 200 °C, whereby the organic compound is at least partially pyrolyzed, and drying the gel. Another aspect of the present invention provides a method for manufacturing a hybrid organic-inorganic silica aerogel or xerogel, the method comprising heating a silica or organosilica gel, which comprises an organic compound, to at least 200 °C; whereby the heating comprises at least partially pyrolyzing the organic compound, and drying the gel, wherein the at least partially pyrolyzing of the organic compound and drying of the silica or organosilica gel are part of the same step or the drying is subsequent to the pyrolyzing; and wherein the organic compound is a bio-monomer, bio-oligomer, synthetic polymer, biopolymer, or a mixture thereof.

[0013] A further aspect provides a hybrid organic-inorganic silica aerogel, obtainable or obtained by the method of the invention.

[0014] Another aspect of the present invention provides a hybrid organic-inorganic silica aerogel or xerogel, obtainable or obtained by the method of the invention, having a specific capacitance of 20-100 F g’1, preferably 50-200 F g’1, preferably 100-300 F g'1; and / or a mass extinction coefficient in the wavelength range of 2.3-10 pm of 10-50 m2kg'1, preferably 30-100 m2kg' preferably higher than 100 m2kg'1; optionally, a surface contact angle of greater than 100°; optionally, a thermal conductivity of less than 25 mW / m-K at 25°C; optionally, a 24-h water uptake of less than 15%.

[0015] These and further aspects and preferred embodiments of the invention are described in the following sections and in the appended claims. The subject-matter of the appended claims is hereby specifically incorporated in this specification.

[0016] DESCRIPTION OF EMBODIMENTS

[0017] As used herein, the singular forms “a”, “an”, and “the” include both singular and plural referents unless the context clearly dictates otherwise.

[0018] The terms “comprising”, “comprises” and “comprised of’ as used herein are synonymous with “including”, “includes”, “containing”, or “contains”, and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps. The terms also encompass “constituted of’, “consists in”, “consisting of’, and “consists of’, and also the terms “consisting essentially of’, “consisting essentially in” and “consists essentially of’, which enjoy well-established meanings in patent terminology. The recitation of numerical ranges by endpoints includes all integer numbers and, where appropriate, fractions subsumed within the respective ranges, as well as the recited endpoints. This applies to numerical ranges irrespective of whether they are introduced by the expression “from. . . to. . .” or the expression “between. . . and. ..” or another expression. Any numerical range recited herein is intended to include all sub-ranges subsumed therein.

[0019] The terms “about” or “approximately” as used herein when referring to a measurable value such as a parameter, an amount, a temporal duration, and the like, are meant to encompass variations of and from the specified value, such as variations of + / -10% or less, preferably + / -5% or less, more preferably + / -1% or less, and still more preferably + / -0.1% or less of and from the specified value, insofar such variations are appropriate to perform in the disclosed invention. It is to be understood that the value to which the modifier “about” or “approximately” refers is itself also specifically, and preferably, disclosed.

[0020] Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order, unless specified. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0021] Whereas the terms “one or more” or “at least one”, such as one or more members or at least one member of a group of members, is clear per se, by means of further exemplification, the term encompasses inter alia a reference to any one of said members, or to any two or more of said members, such as, e.g., any >3, >4, >5, >6 or >7 etc. of said members, and up to all said members. In another example, “one or more” or “at least one” may refer to 1, 2, 3, 4, 5, 6, 7 or more.

[0022] As used herein, the term “and / or” when used in a list of two or more items, means that any one of the listed items can be employed by itself or any combination of two or more of the listed items can be employed. For example, if a list is described as comprising group A, B, and / or C, the list can comprise A alone, B alone, C alone, A and B in combination, A and C in combination, B and C in combination, or A, B, and C in combination. As used throughout the present disclosure, the terms “weight %” or “% w / w” or “% by weight” are used interchangeably and refer to the weight concentration of a constituent, i.e. the weight of a constituent divided by the total weight of all constituents.

[0023] The term "alkyl" as a group or part of a group, refers to a hydrocarbyl group of formula CnH2n+i wherein n is a number greater than or equal to 1. Alkyl groups may be linear or branched and may be substituted as indicated herein. Generally, alkyl groups of this invention comprise from 1 to 18 carbon atoms, preferably from 1 to 10 carbon atoms, preferably from 1 to 6 carbon atoms, more preferably from 1 to 4 carbon atoms. When a subscript is used herein following a carbon atom, the subscript refers to the number of carbon atoms that the named group may contain. For example, the term "Ci-2oalkyl", as a group or part of a group, refers to a hydrocarbyl group of formula -CnFbn+i wherein n is a number ranging from 1 to 20. Thus, for example, “Ci-salkyl” includes all linear or branched alkyl groups with between 1 and 8 carbon atoms, and thus includes methyl, ethyl, n-propyl, i- propyl, butyl and its isomers (e.g. n-butyl, i-butyl and t-butyl); pentyl and its isomers, hexyl and its isomers, etc. A “substituted alkyl" refers to an alkyl group substituted with one or more substituent(s) (for example 1 to 3 substituent(s), for example 1, 2, or 3 substituent(s)) at any available point of attachment.

[0024] When the suffix "ene" is used in conjunction with an alkyl group, i.e. “alkylene”, this is intended to mean the alkyl group as defined herein having two single bonds as points of attachment to other groups. As used herein, the term “alkylene” also referred as “alkanediyl”, by itself or as part of another substituent, refers to alkyl groups that are divalent, i.e., with two single bonds for attachment to two other groups. Alkylene groups may be linear or branched and may be substituted as indicated herein. Non-limiting examples of alkylene groups include methylene (-CH2-), ethylene (-CH2-CH2-), methylmethylene (-CH(CH3)-), 1- methyl-ethylene (-CH(CH3)-CH2-), n-propylene (-CH2-CH2-CH2-), 2-methylpropylene (- CH2-CH(CH3)-CH2-), 3 -methylpropylene (-CH2-CH2-CH(CH3)-), n-butylene (-CH2-CH2- CH2-CH2-), 2-methylbutylene (-CH2-CH(CH3)-CH2-CH2-), 4-methylbutylene (-CH2-CH2- CH2-CH(CH3)-), pentylene and its chain isomers, hexylene and its chain isomers.

[0025] The term “alkenyl” as a group or part of a group, refers to an unsaturated hydrocarbyl group, which may be linear, or branched, comprising one or more carbon-carbon double bonds. Generally, alkenyl groups of this invention comprise from 3 to 18 carbon atoms, preferably from 3 to 10 carbon atoms, preferably from 3 to 8 carbon atoms. When a subscript is used herein following a carbon atom, the subscript refers to the number of carbon atoms that the named group may contain. Examples of C3-2oalkenyl groups are ethenyl, 2-propenyl, 2- butenyl, 3-butenyl, 2-pentenyl and its isomers, 2-hexenyl and its isomers, 2,4-pentadienyl, and the like.

[0026] The term “aryl”, as a group or part of a group, refers to a polyunsaturated, aromatic hydrocarbyl group having a single ring (i.e. phenyl) or multiple aromatic rings fused together (e.g. naphthyl), or linked covalently, typically containing 6 to 20 atoms; preferably 6 to 10, wherein at least one ring is aromatic. Examples of suitable aryl include Ce-2oaryl, preferably Ce-ioaryl, more preferably Ce-saryl. Non-limiting examples of aryl comprise phenyl, biphenylyl, biphenylenyl, or 1-or 2-naphthanelyl; 1-, 2-, 3-, 4-, 5- or 6-tetralinyl (also known as “1,2,3,4-tetrahydronaphtalene); or 1,2,3,4-tetrahydronaphthyl. A “substituted aryl” refers to an aryl group having one or more substituent(s) (for example 1, 2 or 3 substituent(s), or 1 to 2 substituent(s)), at any available point of attachment.

[0027] The discussion of the background to the invention herein is included to explain the context of the invention. This is not to be taken as an admission that any of the material referred to was published, known, or part of the common general knowledge in any country as of the priority date of any of the claims.

[0028] Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included to better appreciate the teaching of the invention. When specific terms are defined in connection with a particular aspect of the invention or a particular embodiment of the invention, such connotation or meaning is meant to apply throughout this specification, i.e., also in the context of other aspects or embodiments of the invention, unless otherwise defined.

[0029] In the following passages, different aspects or embodiments of the invention are defined in more detail. Each aspect or embodiment so defined may be combined with any other aspect(s) or embodiment s) unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous. Reference throughout this specification to “one embodiment”, “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the appended claims, any of the claimed embodiments can be used in any combination.

[0030] Similarly, it should be appreciated that in the description of illustrative embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects.

[0031] As corroborated by the experimental section, which illustrates certain representative embodiments of the present invention, the inventor has demonstrated that hybrid organic- inorganic silica aerogels or xerogels can be highly efficiently manufactured to obtain a hydrophobic and opacified material for long-term thermal insulation, without collapse of the cell structure.

[0032] Accordingly, an aspect of the invention provides a method for manufacturing a hybrid organic-inorganic silica aerogel or xerogel, comprising heating a silica or organosilica gel which comprises an organic compound to at least 200 °C, whereby the organic compound is at least partially pyrolyzed, and drying the gel.

[0033] The term “aerogel”, as used herein, has a well established meaning within the art and is intended to have the meaning as understood in the art. By means of further guidance and without limitation, an aerogel may particularly encompass a solid object comprising a network of interconnected solid structures and pores. Aerogels are typically derived from a corresponding gel in which the liquid component within the network of interconnected pores has been replaced with a gas. The term “xerogel”, as used herein, has a well established meaning within the art and is intended to have the meaning as understood in the art. By means of further guidance and without limitation, a xerogel may particularly encompass a solid object comprising an open polymer network comprising a compact structure. Unlike aerogels, xerogels may be dried to yield a denser structure with reduced porosity.

[0034] Aerogels or xerogels are generally prepared by removing the solvent from a gel (i.e., a solid network that contains a solvent) in a manner such that minimal or no contraction of the gel can be brought by capillary forces at its pore walls, in other words, by the removal of all swelling agents from a corresponding wet-gel without substantial volume reduction or network compaction. Advantageously, and in contrast to the prior art, the present invention may allow to simultaneously remove solvent from the gel and pyrolyze at least a part of an organic compound to provide the resulting aerogel or xerogel with desirable properties, including good hydrophobicity and thermal insulation.

[0035] In particular embodiments of the invention, the method for manufacturing a hybrid organic- inorganic silica aerogel or xerogel, comprises supercritically drying a silica or organosilica gel which comprises an organic polymer by heating the silica or organosilica gel to at least 200 °C, whereby the organic polymer is at least partially pyrolyzed.

[0036] The terms silica or organosilica gel as used herein refer to a composition comprising a silica or organosilica network and a pore liquid. The term silica network as used herein preferably refers to a composition comprising a polycondensation product of a silica source derived from a silica-containing feedstock. The term organosilica network as used herein preferably refers to a composition comprising the polycondensation product of the silica source and one or more organic molecule that is bound to the silica gel, wherein organic radical R is directly bonded via silica atoms or bonded via oxygen atoms to the silica gel. As used herein, the silica or organosilica gel further comprises an organic compound.

[0037] The term polycondensation as used herein refers to a reaction of at least two steps wherein the silica source is hydrolysed first to produce a sol and subsequently condensed to produce a silica or organosilica gel. In some embodiments, condensation reactions may take place in parallel to the hydrolysis of the silica source. In some embodiments, condensation reactions may comprise the reaction of silanol groups to form siloxane bonds. In some embodiments, the dispersed particles in the sol may form aggregates or oligomers (small polymers). In some embodiments, in a first stage, the aggregates or oligomers may grow by further aggregation or polymerization, respectively. In some embodiments, in a second stage, the aggregates or oligomers may bond with each other to form a continuous cluster or network that spans the liquid. In some embodiments, the formation and grow of aggregates and oligomers may occur via condensation reactions. In some embodiments, aggregation and polymerization may comprise the formation of siloxane bonds. In some embodiments, the formation of a continuous cluster or network that spans the liquid may result in a gel. In some embodiments, the formation of a continuous cluster or network composed of silica nanostructures that spans the liquid may result in a silica or organosilica gel. The conversion of sol to gel may also be termed gelation. In some embodiments, the conversion of the sol to the gel may take about a few seconds. In some embodiments, the conversion of the sol to the gel may take about a few minutes. In some embodiments, the conversion of the sol to the gel may take about 15 minutes or more. In some embodiments, the conversion of the sol to the gel may take about 30 minutes or more. In some embodiments, the conversion of the sol to the gel may take about 1 hour. In some embodiments, the conversion of the sol to the gel may take about 4 hours. In some embodiments, the conversion of the sol to the gel may take about 8 hours. In some preferred embodiments, the conversion of the sol to the gel takes less than 12 hours. In some embodiments, condensation reactions may still take place after the formation of a gel. In some embodiments, the gel may be allowed to sit, which may be referred to herein as “aging”. In some embodiments, aging may take place at a temperature in the range from about room temperature to 60°C. In some embodiments, gels may age at a temperature in the range from about room temperature to 60°C generated by dielectric heating such as microwave radiation.

[0038] Silica gels may be produced from the polycondensation of various silica sources, comprising natural sources and / or industrial sources. In some embodiments, the natural source may comprise rice, sugarcane bagasse, bamboo, horsetail (equisetum), oat straw, wheat straw, barley straw, sand, quartz, diatomite, volcanic ash, olivine, silicates, or zeolite. In some embodiments, the natural source may comprise rice, sugarcane bagasse, bamboo, horsetail (equisetum), oat straw, wheat straw, barley straw, sand, quartz, diatomite, volcanic ash, silicates, or zeolite. Other natural sources are possible. In some embodiments, the industrial source for silica may comprise silica sand, silica derived from fumed silica, silica derived from precipitated silica, silica derived from silica gel, silica derived from silica xerogel, silica derived from glass, silica derived from glass cullet, silica derived from fused silica, silica derived from glass fiber, silica derived from fly ash, silica derived from bottom ash, silica derived from slag, or silica derived from other waste streams. In some embodiments, the industrial source for silica may comprise silica sand, silica derived from fumed silica, silica derived from silica gel, silica derived from glass, silica derived from glass fiber, silica derived from fly ash, silica derived from bottom ash, silica derived from slag, or silica derived from other waste streams. Other silica sources are possible. In some embodiments, the silica source may receive one or more treatments before use. In some embodiments, the treatment of the silica source may comprise comminution, pulverization, cutting, grinding, chopping, milling, smashing, cleavage, dissolution, solvation, precipitation, boiling, heating, combustion, incineration, pyrolysis, calcination, pressurization, purification, extraction, superheated steaming, washing, rinsing, cleansing, leaching, acid treatment, base treatment, separation, filtration, sieving, dehydration, drying, blow drying, irradiation, sonication, or combinations thereof. Other treatments are possible and may be included in the treatment process. In some embodiments, the preferred treatment or the combination of preferred treatments may depend on the silica source. In some embodiments, said silica source may comprise tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetratert-butoxysilane. In some preferred embodiments, the silica source may comprise tetramethoxysilane and tetraethoxysilane, tetraisopropxysilane. In some embodiments, the silica source may comprise an alkali silicate. In a particular aspect of the invention, the silica source may be converted to a sol-gel material. In some embodiments, the as-obtained silica gel may be dried immediately.

[0039] Organosilica gels may be produced from the polycondensation of the silica source and one or more organic molecule that is bound to the silica gel, wherein organic radical R is directly bonded via silica atoms or bonded via oxygen atoms to the silica gel. In preferred embodiments, the organosilica gel comprises at least one organic radical R bonded directly via silica atoms to the gel. Examples of suitable organic radicals R are alkyl, alkylene, alkenyl and aryl. The organic radical R is preferably alkyl or aryl. Particularly preferred alkyl radicals are methyl and propyl. A preferable aryl radical is phenyl.

[0040] In some embodiments, the one or more organic molecule has one or more hydroxyl functional groups that may react with metalloid oxides to form an alkoxide. The formed alkoxide may further react with silicon oxides to form a silicon alkoxide blend. Suitable silican alkoxides as used herein are compounds that may be represented by the general formula SiRn(ORa)m, in which R is an organic radical as defined herein above; ORaor -ORais an alkoxy group; n is an integer from 0 to 4; and m is an integer from 0 to 4. Hence, when silicon alkoxides are discussed in the present specification, the specification may typically concern blends of silicon alkoxides resulting from the recited reactions. In some embodiments, the alkoxide blend may be formed in the presence of one or more catalysts. In a particular aspect of the invention, the alkoxide blend may be converted to a sol-gel material, wherein the one or more organic molecule is bound to the silica gel. In some embodiments, the as-obtained organosilica gel may be dried immediately. In some embodiments, the produced alkoxide may be monomeric or oligomeric (dimeric, trimeric, tetrameric, pentameric, hexameric, heptameric, octameric, nonameric, decameric). In some embodiments, the oligomeric alkoxide may contain more than ten (decameric) repeating units. In some embodiments, part of the one or more organic molecule that has one or more hydroxyl functional groups may be recovered from the extraction of the pore liquid of the gel during drying. In some embodiments, recovered hydroxyl-containing organic molecules may be used to make another (silicon) alkoxide.

[0041] In some embodiments, the (silicon) alkoxide may contain a number of silicon atoms ranging from 1 to 10. In some embodiments, the alkoxide may contain a number of silicon atoms ranging from 1 to 7. In some embodiments, the alkoxide may contain a number of silicon atoms ranging from 1 to 5. In some preferred embodiments, the alkoxide may contain a number of silicon atoms ranging from 1 to 3. In some embodiments, at least 70 mol% of the formed alkoxides may contain a number of silicon atoms ranging from 1 to 3. In some embodiments, at least 80 mol% of the formed alkoxides may contain a number of silicon atoms ranging from 1 to 3. In some embodiments, at least 90 mol% of the formed alkoxides may contain a number of silicon atoms ranging from 1 to 3. In some preferred embodiments, at least 95 mol% of the formed alkoxides may contain a number of silicon atoms ranging from 1 to 3.

[0042] In some embodiments, the one or more organic molecule comprises an alcohol. Alcohols may encompass organic molecule in which a hydroxyl group (-OH) is attached to a saturated carbon atom.

[0043] In some embodiments, the alcohol is an alkyl alcohol preferably having the formula Rb-OH wherein Rbis alkyl as defined herein. In some embodiments, the alkylchain (i.e., Rb) of the alcohol may have 1 to 18 carbon atoms, such as for example 1 to 5 carbon atoms. In some embodiments, the alcohol comprises methanol, ethanol, isopropanol, n-propanol, tertbutanol, sec-butanol, n-butanol, n-pentanol, n-hexanol, and / or an amyl alcohol (primary, secondary, and / or tertiary). Other alcohols are possible. In some preferred embodiments, the alcohol may be methanol, ethanol, isopropanol, or tert-butanol. In some embodiments, a combination of different alcohols may be used. In some embodiments, the alcohol may be an alkenyl alcohol preferably having the formula RC-OH wherein Rcis alkenyl as defined herein. In some preferred embodiments, the unsaturated alcohol may be selected from the group comprising ethenol (vinyl alcohol), l-propen-2-ol (prop-l-en-2-ol), 2-propen-l-ol (prop-2-en-l-ol, allyl alcohol), 3-buten-l-ol (allyl carbinol), 3-buten-2-ol (methyl vinyl carbinol), 4-penten-l-ol, 3-methyl-3-buten-l-ol (isoprenol), 5-hexen-l-ol. Other unsaturated alcohols may be possible. In yet further preferred embodiments, ethenol (vinyl alcohol) and / or 3-buten-l-ol (allyl carbinol) may be used.

[0044] In some embodiments, the one or more organic molecule comprises a fatty acid. In some embodiments, a fatty acid may be a carboxylic acid with a saturated or unsaturated aliphatic chain. In some embodiments, the chain of the fatty acid may have 8 to 26 carbons, although fatty acids with chains of fewer or more carbons exist as well. In some embodiments, the fatty acid may be obtained from triglycerides from a natural source such as fats and oils found in plants. In some embodiments, the saturated fatty acid comprises caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, and / or cerotic acid. Other saturated fatty acids are possible. In some preferred embodiments, the saturated fatty acid may be palmitic and / or stearic acid. In some embodiments, the unsaturated fatty acid comprises myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, arachidonic acid, and / or erucic acid. Other unsaturated fatty acids are possible. In some preferred embodiments, the unsaturated fatty acid may be oleic and / or linoleic acid.

[0045] In some embodiments, the one or more organic molecule comprises a fatty alcohol. In some embodiments, the fatty alcohol is an alcohol with a saturated or unsaturated aliphatic chain. In some embodiments, the fatty alcohol is an alcohol having the formula Rd-0H wherein Rdis alkyl or an alkenyl as defined herein above. In some embodiments, the fatty alcohol may be an aliphatic alcohol typically consisting of a chain of 8 to 26 carbons, although fatty alcohols with chains of fewer or more carbons exist as well. In some embodiments, the fatty alcohol may be obtained from a natural source such as fats and oils found in plants. In some embodiments, a fatty alcohol may be obtained from a fatty ester. In some embodiments, a fatty alcohol may be obtained by reacting a fatty ester with hydrogen gas (H2) at elevated temperature and pressure. In some embodiments, a fatty alcohol may be obtained by reacting a fatty ester with hydrogen gas (H2) at supercritical conditions. In some embodiments, the fatty alcohol comprises capryl alcohol (1 -octanol), pelargonic alcohol (1-nonanol), capric alcohol (1-decanol), hendecanol (1 -undecanol), lauryl alcohol (1 -dodecanol), myristyl alcohol (1 -tetradecanol), cetyl alcohol (1 -hexadecanol), palmitoleyl alcohol (cis-9- hexadecen-l-ol), stearyl alcohol (1 -octadecanol), oleyl alcohol (1 -octadecenol), arachidyl alcohol (1-eicosanol), behenyl alcohol (1 -docosanol), erucyl alcohol (cis-13-docosen-l-ol), and / or ceryl alcohol (1-hexacosanol). In some preferred embodiments, the fatty alcohol may be lauryl, stearyl, or oleyl alcohol.

[0046] In some embodiments, silica or organosilica gels are provided in the form of monoliths, chunks, granules, aggregates, particles, or a combination thereof. In some embodiments, gels provided in the form of monoliths, chunks, granules, aggregates, particles, or a combination thereof, may be regular in shape. In some embodiments, gels are provided in the form of monoliths, chunks, granules, aggregates, particles, or a combination thereof, may be irregular in shape. In some embodiments, a portion of the gels provided in the form of monoliths, chunks, granules, aggregates, particles, or a combination thereof, may be regular in shape. In some embodiments, gels provided in the form of monoliths, chunks, granules, aggregates, particles, or a combination thereof, may be pulverized into smaller particles or powder before drying. In some embodiments, smaller gel particles may dry faster than larger gel particles or gel monoliths. In some embodiments, drying of gel particles may result in aerogel or xerogel particles. In some embodiments, aerogel or xerogel particles comprise aerogel or xerogel granules and / or aerogel or xerogel powder.

[0047] The silica or organosilica gels as used herein refers to a composition comprising a solid, nanoporous silica or organosilica network and a pore liquid. The pore liquid permeates the pores of the silica or organosilica network and is extracted from the network to produce a silica or organosilica aerogel or xerogel. In some embodiments, the pore liquid comprises compounds that are not bound to the silica or organosilica gel after gelation. In some embodiments, the pore liquid may further comprise catalyst, water, salts or mixtures thereof. In preferred embodiments, the pore liquid of the silica or organosilica gel is purified before drying said silica or organosilica gel. Purification of the pore liquid comprises swelling of the silica or organosilica gel in a solvent, wherein impurities diffuse out of the network structure and solvent diffuses in. In preferred embodiments the pore liquid comprises a solvent, wherein the solvent is selected from the group consisting of liquid CO2, alcohol, alkane, ether, and a mixture thereof. In some embodiments, the solvent is selected from the group consisting of alkyl alcohol, alkane, alkyl ether, and a mixture thereof. In some embodiments, the solvent is selected from the group consisting of Ci-isalkyl alcohol, Ci- isalkane, Ci-isalkyl ether. In some preferred embodiments the solvent is selected from the group consisting of methanol, ethanol, propanol, isopropanol, butanol, sec-butanol, isobutanol, tert-butanol, and mixtures thereof. In the most preferred embodiments, the pore liquid comprises methanol, ethanol, propanol, or mixtures thereof. In some preferred embodiments, the solvent is selected from the group consisting of pentane, hexane, heptane, octane, nonane or mixtures thereof. In some preferred embodiments, the solvent is selected from the group consisting of diethyl ether, methyl- / c / 7-buthyl ether, or mixtures thereof.

[0048] The silica or organosilica gel as used herein further comprises an organic compound. The organic compound may comprise at least one and typically a plurality of functional groups capable of interacting or reacting with the silica or organosilica network. Preferably such functional group or groups may be polar group(s), such as preferably oxygen-containing polar group(s), such as more preferably hydroxyl group(s) or carboxyl groups, even more preferably hydroxyl group(s). In some embodiments, the organic compound becomes non- covalently associated with or bound to the silica or organosilica gel. In some embodiments, the organic compound becomes covalently bound to the silica or organosilica gel. In certain embodiments, organic compound may be able to mechanically reinforce the silica network by crosslinking silanol groups, such as in particular non-adjacent silanol groups. In some embodiments, the organic compound may partially hydrophobize the silica network by eliminating free silanol groups.

[0049] In some embodiments, the organic compound comprises a monomer or small molecule. Monomers or small molecules may encompass organic compounds selected from the group consisting of monosaccharide, amino acid, glucosinolate, nucleotide, phenol, tryptophol, indole-3 -carbinol, serotonin, a hydroxy fatty acid, and mixtures thereof. In other words, the organic compound as disclosed herein may encompass one or more bio-monomers. The term “bio-monomers” or “biomonomers”, as used herein interchangeably, has a well established meaning within the art and is intended to have the meaning as understood in the art. By means of further guidance and without limitation, a bio-monomer is a compound that is typically derived from biological resources such as carbohydrates, amino acids, nucleotides, or lipids.

[0050] In some preferred embodiments, monosaccharides may comprise glucose, fructose, galactose, deoxyribose, dihydroxyacetone (glycerone), glyceraldehyde, erythrose, threose, ribose, arabinose, xylose, lyxose, allose, altrose, mannose, idose, talose, mannoheptulose, sedoheptulose. In further embodiments, a monosaccharide may be a cyclic form of a monosaccharide selected from the group comprising furanoses, pyranoses, or a combination thereof. In some embodiments, the furanose may comprise glucofuranose, fructofuranose, galactofuranose, deoxyribofuranose, erythrofuranose, threofuranose, ribofuranose, arabinofuranose, xylofuranose, lyxofuranose, allofuranose, altrofuranose, mannofuranose, idofuranose, talofuranose. In some embodiments, the pyranose may comprise glucopyranose, fructopyranose, galactopyranose, deoxyribopyranose, erythropyranose, threopyranose, ribopyranose, arabinopyranose, xylopyranose, lyxopyranose, allopyranose, altropyranose, mannopyranose, idopyranose, talopyranose. Other monosaccharides may be used.

[0051] In some embodiments, the organic compound comprises a derivative of a monosaccharide. Derivatives of monosaccharide may encompass organic compounds selected from the group consisting of: amino sugar, sulfosugar, sugar alcohol, sugar acid, and mixtures thereof. In some embodiments, the amino sugar may comprise galactosamine, glucosamine, sialic acid, N-acetylglucosamine. In some embodiments, the sulfosugar may comprise sulfoquinovose. In some embodiments, the sugar alcohol may comprise mannitol. In some embodiments, the sugar acid may comprise ascorbic acid, glucuronic acid. Other derivatives of monosaccharides may be used.

[0052] In some embodiments, the organic compound comprises an oligomer. Oligomers may encompass organic compounds selected from the group consisting of: oligosaccharides, oligopeptides, oligonucleotides, and mixtures thereof. In other words, the organic compound as disclosed herein may encompass one or more bio-oligomers. The term “bio-oligomers” or “biooligomers”, as used herein interchangeably, has a well established meaning within the art and is intended to have the meaning as understood in the art. By means of further guidance and without limitation, a bio-oligomer is a short chain molecule composed of biologically derived monomer units, typically ranging from 2 to 20 units. Typical biological resources of bio-oligomers include carbohydrates, amino acids, nucleotides, or lipids.

[0053] In some embodiments, oligosaccharides as disclosed herein may comprise between 2 and 10 monosaccharide units, such as 2, 3, 4, 5, 6, 7, 8, or 9 monosaccharide units. An oligosaccharide with 2 monosaccharide units is also known in the art as a disaccharide.

[0054] In preferred embodiments, oligosaccharides may comprise oligomeric carbohydrates selected from the group consisting of disaccharides, trisaccharides, tetrasaccharides, and mixtures thereof. In some embodiments, disaccharides may comprise cellobiose, sucrose, lactose, maltose, trehalose, chitobiose. Other disaccharides may be used. In some embodiments, trisaccharides may comprise cellotriose, maltotriose, nigerotriose, melezitose, maltotriulose, raffinose, kestose. Other trisaccharides may be used. In some embodiments, tetrasaccharides may comprise cellotetraose, lychnose, maltotetraose, nigerotetraose, nystose, sesamose, stachyose. Other tetrasaccharides may be used. In some embodiments, oligosaccharides comprising of a network constructed of more than four monosaccharides structures may be used. In some embodiments, the organic compound comprises a biopolymer. Biopolymers may encompass compounds selected from the group consisting of: polysaccharide, polypeptide, polynucleotide, tannin, melanin, cutin, cutan, latex, rubber, and mixtures thereof. The term “bio-polymers” or “biopolymers”, as used herein interchangeably, has a well established meaning within the art and is intended to have the meaning as understood in the art. By means of further guidance and without limitation, a bio-polymer is a polymer that is derived from biological sources or synthesized using biological processes.

[0055] In preferred embodiments polysaccharides are selected from the group consisting of: cellulose, nanocellulose, nanofibrillated cellulose, hemicellulose, xylan, lignin, lignosulfonate, chitin, pectin, arabinoxylan, starch, glycogen, inulin, xanthan gum, guar gum, agar, agarose, alginate, chitosan, heparin, and mixtures thereof. Other polysaccharides may be used. In some embodiments, cellulose, hemicellulose, and / or lignin may be derived from a natural source comprising plants, trees, biomass, wood, wood pulp, plant stems, plant fiber, plant husk, cotton, flax, jute, sugarcane, bagasse, grass, bamboo, cereals, bacteria. In some embodiments, plant stems may comprise hemp, linen, and manila. In some preferred embodiments, cellulose may be derived from an industrial waste source comprising paper, cardboard, wood, wood pulp, sawdust, textiles, cotton, flax, linen, regenerated cellulose. In some embodiments, lignin may comprise a polymer of phenylpropane units interconnected and crosslinked to each other via variety of chemical bonds. In some embodiments, lignin may comprise kraft lignin, sulfonated lignin, soda lignin, and a mixture thereof.

[0056] In some embodiments, the organic compound comprises a cellulosic material. Cellulosic materials may encompass compounds selected from the group consisting of: microcrystalline cellulose, microbial cellulose, nanocellulose, nanofibrillated cellulose, cellulose nanofibers, nanocrystalline cellulose, cellulose nanocrystals, bacterial nanocellulose, and mixtures thereof. Other cellulosic material may be used. In some embodiments, nanofibrillated cellulose may comprise cellulose particles having an elongated form, having an aspect ratio larger than 1, having an average length in the range of 15 to 900 nm, preferably in the range of 50 to 700 nm, more preferably in the range of 70 to 700 nm; while having an average thickness in the range of 3 to 200 nm, preferably in the range of 5 to 100 nm, more preferably in the range of 5 to 30 nm.

[0057] In some embodiments, the organic compound comprises a hemicellulosic material. Hemicellulosic materials may encompass compounds selected from the group consisting of: xylose, arabinose, mannose, galactose, deoxy sugar rhamnose, and mixtures thereof. In some embodiments, hemicellulose may contain acidified forms of sugars, comprising glucuronic acid and galacturonic acid.

[0058] In some embodiments, the organic compound comprises a synthetic polymer. Synthetic polymers may encompass compounds selected from the group consisting of: polyamide, polyimide, polyacrylamide, polyacrylate, polyacrylonitrile, polycyanurate, polyurea, polyurethane, polyisocyanurate, polyaramid, polyester, polyamine, polycarbonate, polyether, polyol, polyvinyl alcohol, polyvinyl alcohol dialdehyde, polyvinyl ester, polyaldehyde, phenolic resin, resorcinol formaldehyde (polymer / resin), phenol formaldehyde (polymer / resin), melamine formaldehyde (polymer / resin), cresol formaldehyde (polymer / resin), phenol furfuryl alcohol, polyepoxide (epoxy), and mixtures thereof.

[0059] In some embodiments, the organic compound may be bound to remaining silanol groups on the silica or organosilica network of the gel. In some embodiments, elimination of remaining silanol groups on the silica network by reactions with sterically-hindered hydrophobic groups and / or organic compounds may prevent the pore walls (struts) of the silica backbone to stick to each other upon shrinkage of the gel during evaporative drying. In some embodiments, elimination of remaining silanol groups on the silica network of the gel may enable shrinkage of the gel to be prevented, minimized or reversed.

[0060] The term “pyrolysis” as used herein refers to thermal decomposition by heating of the silica or organosilica gel in the absence of oxygen and changing the chemical composition. The term “partial pyrolysis”, as used herein indicates that the pyrolysis may not be complete, and some original chemical constituents may remain in the resulting material. The skilled person understands that the extent of pyrolysis can be controlled by adjusting the temperature and time of heating to achieve specific desired properties or compositions in the final product.

[0061] At least partial pyrolysis of the organic compound comprised in the silica or organosilica gel may result in carbonaceous nanostructures. In some embodiments, pyrolysis may comprise any pyrolytic reaction selected from the group consisting of: carbonization, graphitization, coalification, torrefi cation, aromatization, charring, destructive distillation, dehydrogenation, dehydration, condensation, melting, hydrogen transfer, isomerization, decomposition, depolymerization, volatilization, combustion, and wherein some or all of these reactions may take place concurrently.

[0062] In some embodiments, destructive distillation may be achieved at a temperature of at least 200°C, such as of at least 250°C, such as of at least 300°C, such as of at least 350°C, such as of at least 400°C. In some embodiments, destructive distillation may be performed in the absence of air, the absence of oxygen, or in the presence of a limited amount of oxygen and / or other gases or compounds, or in an inert atmosphere. In some embodiments, an inert atmosphere may be achieved using a noble gas. In some embodiments, a noble gas may comprise helium, neon, krypton, argon, xenon, radon. In some embodiments, the inert atmosphere may be achieved using carbon dioxide or nitrogen gas. In some embodiments, carbon dioxide, methane or other carbon-containing gases may be used during pyrolysis. In some embodiments, a higher carbon content may be obtained with a higher pyrolysis temperature. In some embodiments, pyrolysis may be performed in the presence of a catalyst. In some embodiments, the catalyst may be a zeolite. In some embodiments, the silica or organosilica gel is completely pyrolyzed at a temperature of at least 500 °C, such as of at least 550 °C, such as of at least 600 °C, of at least 650 °C, such as of at least 700 °C. In some embodiments, the carbonaceous nanostructures may comprise carbon-rich products and for instance wherein the carbonaceous nanostructures comprise char, charcoal, tar, biooil, ash, sugars, anhydrosugars, furans, furanic compounds, pyrans, phenols, phenolic compounds, (mono)lignols, carbon, activated carbon, graphite, and mixtures thereof.

[0063] Without wishing to be bound by theory, the carbonaceous structure, integrated into the silica network of the aerogel or xerogel after pyrolysis, provides the latter with hydrophobicity, reduction in radiative thermal transport via opacification, and / or improved mechanical strength. In other words, the carbonaceous structure is present in the aerogel or xerogel in an amount capable of providing hydrophobicity and opacification to the aerogel or xerogel. In some embodiments, pyrolysis may proceed at an elevated pressure. In some embodiments, the reaction pressure may be higher than the atmospheric pressure (such as about 0.101325 MPa). In some embodiments, the reaction pressure may be higher than 1 MPa. In some embodiments, the reaction pressure may be 20 MPa or less. In some preferred embodiments, the reaction pressure may be about 1-10 MPa.

[0064] In some embodiments, pyrolysis may be performed at a temperature of at least 240 °C to at least 300 °C. In some embodiments, the reaction temperature is no more than 400 °C, such as no more than 390°C, no more than 380°C, no more than 370°C, no more than 360°C, no more than 350°C, or no more than 340°C. In some embodiments, heating may be performed via dielectric heating. In some embodiments, dielectric heating may be referred to as heating by application of electromagnetic waves. In some preferred embodiments, the electromagnetic waves produced with dielectric heating are microwaves. In some embodiments, dielectric heating comprises heating via microwave radiation. In some embodiments, the microwave radiation may be generated by a magnetron. In some preferred embodiments, the frequency of the radiation may be between 0.5 GHz and 5 GHz. In some embodiments, the microwave power may be between about 200-700 W. In some preferred embodiments, the microwave power may be about 400-600 W.

[0065] In particular embodiments, heating and drying of the silica or organosilica gel are part of the same step, for example they take place at least partly concurrently.

[0066] In some embodiments, pyrolysis of the organic compound comprised in the silica or organosilica gel and drying of the gel is induced, carried out, or performed separately. In some embodiments, pyrolysis of the organic compound comprised in the silica or organosilica gel is performed first, wherein the pore liquid is still present.

[0067] In particular embodiments, heating and drying of the silica or organosilica gel are separate steps, i.e., the gel is first heated to initiate the at least partial pyrolysis of the organic compound, and the gel with the at least partially pyrolyzed organic compound is subsequently dried.

[0068] In some embodiments, at least partial drying of the silica or organosilica gel results in the formation of a silica or organosilica aerogel or xerogel. In some embodiments drying may comprise removal of the pore liquid via supercritical extraction, subcritical extraction, or freeze drying. In some embodiments drying of the silica or organosilica gel is performed at a temperature of at least 200 °C, at least 220 °C, at least 240 °C, at least 260 °C, at least 280 °C, at least 300 °C, or at least 325 °C. In some embodiments drying of the silica or organosilica gel is performed at a temperature of no more than 400 °C, such as no more than 390°C, no more than 380°C, no more than 370°C, no more than 360°C, no more than 350°C, or no more than 340°C. In some embodiments drying of the silica or organosilica gel is performed at a temperature of at most 200 °C, at most 160 °C, at most 150 °C, at most 130 °C, at most 100 °C, at most 85 °C, at most 65 °C, at most 45 °C, or at most 30 °C. Here, the chosen temperature will depend on the boiling point of the solvent or pore liquid to be extracted and the mode of extraction. In some preferred embodiments drying of the silica or organosilica gel is performed under supercritical pressure. In some embodiments drying of the silica or organosilica gel is performed under subcritical pressure. In some embodiments drying of the silica or organosilica gel is performed under ambient or atmospheric pressure (such as about 0.101325 MPa). Drying of the silica or organosilica gel is continued until the moisture content of the gel is at least below 5 wt%, at least below 3 wt%, or at least below 1 wt%. Preferably the moisture content of the gel after drying comprises between 1 wt% and 0.01 wt%.

[0069] In some embodiments, aerogels may be synthesized by removal of the pore liquid with minimal to no change to the porous nanostructured solid network of the silica or organosilica gel by supercritically extracting the pore liquid from the gel, which is also referred to as “supercritical drying”. Supercritical drying is the original method to obtain an aerogel, in which the pore liquid is first converted into a supercritical fluid, which may be extracted. The term “supercritical liquid” as used herein refers to a liquid near and / or past its critical point, that exhibits little to no surface tension. In some embodiments, the supercritical liquid exhibits no surface tension and thus exerts no capillary forces when removed from the porous gel network, thus preventing collapse of the latter. In some embodiments, supercritical drying involves conditions at elevated temperatures and / or pressures near and / or past the critical point of the pore liquid, which may be provided by a heavy-wall pressure vessel. In some embodiments, the same heavy -wall pressure vessel for preparing the silicon alkoxides may be used. In some embodiments, the heavy-wall pressure vessel may be an autoclave.

[0070] Two main considerations may need to be taken into account in order to successfully dry silica or organosilica gels and obtain xerogels via ambient pressure drying. The first requirement may be hydrophobization, more specifically the replacement of the free silanol groups on the silica backbone of the gel by hydrophobic groups, which may prevent the formation of siloxane bonds in case of shrinkage of the envelope volume of the gel during drying when the pore walls may be getting close to each other due to capillary stresses. Elimination of remaining silanol groups on the silica network of the gel may enable shrinkage of the gel to be prevented, minimized or reversed. The second consideration next to a hydrophobic gel network in order to obtain xerogel via ambient pressure drying may be that the pore liquid of the gel has a relatively low surface tension in order to minimize capillary stresses during evaporative drying, which may be responsible for shrinkage of the envelope volume. In some embodiments, an organic polymer may react with remaining silanol groups on the silica network. A polymer-reinforced silica network may better withstand capillary stresses during evaporative drying. The presence of pyrolyzed organic compounds may further improve the resistance to capillary stresses during evaporative drying. In preferred embodiments, at least partial pyrolysis occurred prior to drying and / or occurs simultaneously with drying to have minimal to no change to the porous nanostructured solid network of the silica or organosilica gel.

[0071] A third consideration, next to a hydrophobic gel network, in order to obtain xerogel via ambient pressure drying may be that the pore liquid of the gel has a relatively low surface tension, lower than about 30 mN / m and preferably lower than about 20 mN / m, in order to have minimal capillary stresses during evaporative drying, which may be responsible for volumetric shrinkage. The dried silica or organosilica gel can be conventionally classified or denoted as a xerogel when the pore liquid of the silica or organosilica gel is not removed in a supercritical state.

[0072] In some embodiments, the vapor phase generated via evaporation of the pore liquid of the wet silica or organosilica gels may be collected, condensed back to liquid phase, and may be used to make new alkoxides and / or new sols.

[0073] In some embodiments, the weight percentage of the organic compound in the silica or organosilica gel is 0.001-20 wt%, preferably 0.01-10 wt%, more preferably 2-10 wt%, most preferably 5-20 wt% such as wherein the organic compound is introduced into the silica or organosilica gel at the solution or sol state at 0.001-20 wt%, preferably 0.01-10 wt%, more preferably 2-10 wt%, most preferably 5-20 wt% of the solution or sol. In some embodiments, the organic compound is mixed with the silica or organosilica gel at the solution or sol state. In some embodiments, the organic compound is a solid mixed with in the sol state as a powder. More preferably, the organic compound is a solid that is at least partially dissolved to obtain a solution or suspension prior to mixing in the sol state. In some embodiments, the organic compound may react with one or more aggregates and / or oligomers during the solgel process. In some embodiments, the organic compound may react with the spanning cluster during the sol-gel process. In some embodiments, the organic compound may react with one or more remaining reactive functional groups on the silica network of the gel.

[0074] In some embodiments, the organic compound may be integrated into the silica network. In some embodiments, the silica network may be interpenetrated with the organic compound. In some embodiments, the organic compound may conformally coat the interior contour surfaces of the silica network. In some embodiments, the silica network may be reinforced via cross-linking with the organic compound. In some embodiments, the cross-linking may comprise a covalent bond between the organic compound and silicon oxide network. Without wishing to be bound by theory, the organic compound may render the silica network more flexible, may enhance the toughness of the silica aerogel or xerogel, may enhance the compression strength of the silica aerogel or xerogel, may enhance the flexural strength of the silica aerogel or xerogel, and / or may result in less volume shrinkage during evaporative drying of the gel into an aerogel or xerogel.

[0075] In some embodiments, manufacturing of hybrid organic-inorganic silica aerogels or xerogels may occur in a vessel, which may compass a batch reactor, a continuous stirred tank reactor, continuous stirred reactors in series, a plug flow reactor, or a combination thereof. In some embodiments, manufacturing of hybrid organic-inorganic silica aerogels or xerogels may occur in a batch reactor, a continuous stirred tank reactor or a plug flow reactor. Other reactors may be possible. In some embodiments, the optimal reactions conditions may be achieved in the reactor, comprising pressure, temperature, volume, residence time, concentration of reagents / products, enthalpy, internal energy, flow rate. In some embodiments, the reactor may be provided with a dehydrating capability, comprising a water separation film, distillation column, or a (ex-situ) molecular sieve. In some preferred embodiments, the batch reactor is a heavy -wall pressure vessel such as an autoclave. In some embodiments, the silica or organosilica network, pore fluid, organic compound, and other reagents and / or additives may be fed into the batch reactor simultaneously or in a certain sequential order of adding. In some embodiments, the reactor may be charged with carbon dioxide. In some embodiments, a continuous stirred tank reactor may be used. In some embodiments, a plug flow reactor may be used.

[0076] For the manufacturing of porous materials such as aerogels or xerogels, two types of density are used. The term envelope density as used herein refers to the ratio of the mass of solid material to the volume of solid material including the pores and cavities. The term skeletal density as used herein refers to the ratio of the mass of solid material to the volume of solid material excluding the pores and cavities. One of ordinary skill in the art would know that the terms skeletal density and skeletal volume may also be referred to as true density and true volume, respectively.

[0077] In some embodiments, the resulting aerogel or xerogel may exhibit a low envelope density. One of ordinary skill in the art would know how to determine the envelope density of an aerogel or xerogel. In some embodiments, the mass may be accurately measured using a digital analytical balance with a precision of 0.001 g. In some embodiments, in case of simple geometries such as a cube, disc, or cylinder, the measurement of the envelope volume may be performed with the help of digital calipers. In some embodiments, the aerogel or xerogel may come in the form of an irregular-shaped monolith, irregular-shaped granules, and / or powder. In some embodiments, in order to accurately determine the volume of irregularshaped monoliths, irregular-shaped granules, and / or powder, a displaced medium conforming to the irregular surface contours without penetrating the pores may be used, for example by using a GeoPyc 1360 Density Analyzer of Micromeritics. In some embodiments, the resulting aerogel or xerogel may exhibit an envelope density between about 0.05 g / cc (i.e., g / cm3) and about 0.7 g / cc, between about 0.05 g / cc and about 0.6 g / cc, between about 0.05 g / cc and about 0.5 g / cc, between about 0.05 g / cc and about 0.4 g / cc, between about 0.05 g / cc and about 0.3 g / cc, between about 0.05 g / cc and about 0.2 g / cc, between about 0.05 g / cc and about 0.1 g / cc. In some preferred embodiments, the density may be between about 0.05 g / cc and 0.2 g / cc. In some embodiments, the aerogel or xerogel may exhibit an envelope density outside these ranges.

[0078] In some embodiments, the resulting aerogel or xerogel may exhibit low skeletal density. In some embodiments, the mass may be accurately measured using a digital analytical balance with a precision of 0.001 g. In some embodiments, the skeletal volume of specimen may be measured using a pycnometer, for example a Quantachrome Instruments PentaPyc 5200e pycnometer, employing helium as probing gas. In some embodiments, specimens may be dried under a flow of nitrogen or helium prior to measurement to remove adsorbates on the aerogel or xerogel inner and outer surface, such as entrapped gases, water from the humidity of air, or other solvents. In some embodiments, the skeletal density of specimen may be calculated dividing the mass by the skeletal volume. In some embodiments, aerogel or xerogel may exhibit a skeletal density between about 1 g / cc and 2 g / cc, between about 1 g / cc and 1.9 g / cc, between about 1 g / cc and 1.8 g / cc, between about 1 g / cc and 1.7 g / cc, between about 1 g / cc and 1.6 g / cc, between about 1 g / cc and 1.5 g / cc, between about 1 g / cc and 1.4 g / cc, between about 1 g / cc and 1.3 g / cc, between about 1 g / cc and 1.2 g / cc, between about 1 g / cc and 1.1 g / cc, between about 1.4 g / cc and 1.9 g / cc, between about 1.5 g / cc and 2 g / cc, between about 1.6 g / cc and 2.1 g / cc, between about 1.7 g / cc and 2.2 g / cc, between about 3 g / cc and 4 g / cc, between about 4 g / cc and 5 g / cc. In some preferred embodiments, the aerogel or xerogel may exhibit a skeletal density between 1.4 g / cc and 1.8 g / cc.

[0079] In some embodiments, the resulting aerogel or xerogel may exhibit a high porosity. In some embodiments, the resulting aerogel or xerogel may exhibit a porosity of at least 50% and preferably at most 99%. In some embodiments, the resulting aerogel or xerogel may exhibit a porosity of at least 60% and preferably at most 99%, of at least 70% and preferably at most 99%, of at least 80% and preferably at most 99%. In some preferred embodiments, the resulting aerogel or xerogel may exhibit a porosity of at least 90% and preferably at most 99%. In some embodiments, porosity may be defined as the ratio of the pore volume divided by the envelope volume. In some embodiments, the porosity of the aerogel or xerogel may be calculated from its envelope density and skeletal density by subtracting the ratio of envelope density divided by skeletal density from 1 and multiply the result by 100.

[0080] In some embodiments, the resulting aerogel or xerogel may exhibit a high specific surface area. In some embodiments, the resulting aerogel or xerogel may exhibit a specific surface area of at least about 50 m2 / g and preferably at most about 4000 m2 / g, of at least about 100 m2 / g and preferably at most about 4000 m2 / g, of at least about 200 m2 / g and preferably at most about 4000 m2 / g, of at least about 300 m2 / g and preferably at most about 4000 m2 / g, of at least about 400 m2 / g and preferably at most about 4000 m2 / g, of at least about 500 m2 / g and preferably at most about 4000 m2 / g, of at least about 600 m2 / g and preferably at most about 4000 m2 / g, of at least about 700 m2 / g and preferably at most about 4000 m2 / g, of at least about 800 m2 / g and preferably at most about 4000 m2 / g, of at least about 900 m2 / g and preferably at most about 4000 m2 / g, of at least about 900 m2 / g and preferably at most about 4000 m2 / g, of at least about 2000 m2 / g and preferably at most about 4000 m2 / g, of at least about 3000 m2 / g and preferably at most about 4000 m2 / g. In some preferred embodiments, the specific surface area of the aerogel or xerogel is at least about 400 m2 / g and preferably at most about 1200 m2 / g. One of ordinary skill in the art would know how to determine the specific surface area of an aerogel or xerogel, for example, using nitrogen sorption analysis. For example, nitrogen sorption analysis may be performed using a NOVA®-e Series of surface area and pore size analyzers by Quantachrome Instruments. Before sorption analysis, specimens may be subjected to vacuum of -100 torr and heated for 24 hours to remove moisture and / or other solvents adsorbed by the specimens. In some embodiments, the specific surface area may be calculated from the adsorption isotherm using the Brunauer- Emmett-Teller (BET) method over ranges in relative pressure typically employed in measuring surface area, for example relative pressures ranging from 0.1 to 0.3.

[0081] In some embodiments, the resulting aerogel or xerogel may exhibit a pore size distribution ranging from pore sizes smaller than 0.1 nm to pore sizes larger than 200 nm. In some preferred embodiments, the resulting aerogel or xerogel may exhibit a pore size distribution mainly covering mesopores (2-50 nm). In some embodiments, the most frequent pore diameter of the aerogel or xerogel may be in the mesoporous range (2-50 nm). In some embodiments, the most frequent pore diameter of the aerogel or xerogel may be larger than 1 nm. In some embodiments, the most frequent pore diameter of the aerogel or xerogel may be larger than 2 nm. In some embodiments, the most frequent pore diameter of the aerogel or xerogel may be larger than 5 nm. In some embodiments, the most frequent pore diameter of the aerogel or xerogel may be larger than 10 nm. In some embodiments, the most frequent pore diameter of the aerogel or xerogel may be larger than 20 nm. In some embodiments, the most frequent pore diameter of the aerogel or xerogel may be larger than 30 nm. In some embodiments, the most frequent pore diameter of the aerogel or xerogel may be larger than 40 nm. In some embodiments, the most frequent pore diameter of the aerogel or xerogel may be larger than 50 nm. In some embodiments, the most frequent pore diameter of the aerogel or xerogel may be larger than 100 nm. In some preferred embodiments, the most frequent pore diameter of the aerogel or xerogel is smaller than 50 nm. In some preferred embodiments, the most frequent pore diameter of the aerogel or xerogel may be about 2-40 nm. One of ordinary skill in the art would know how to determine the pore size distribution of an aerogel or xerogel, for example, using nitrogen sorption analysis. For example, nitrogen sorption analysis may be performed using a NOVA®-e Series of surface area and pore size analyzers by Quantachrome Instruments. Before sorption analysis, specimens may be subjected to vacuum of -100 torr and heated for 24 hours to remove moisture and / or other solvents adsorbed by the specimens. In some embodiments, the pore size distribution may be calculated from the adsorption or desorption isotherm using the Barrett- Joy ner-Halenda (BJH) method. In some embodiments, the most frequent pore diameter may be obtained from the BJH pore size distribution, more specifically the pore diameter corresponding to the peak or maximum of the distribution curve.

[0082] In some embodiments, aerogel or xerogel produced within the scope of the present invention may comprise a high carbon to silica molar ratio, which is difficult to achieve using production approaches generally known in the art. The “carbon to silica molar ratio” as described herein refers to the molar ratio of carbon from the organic compounds and carbonaceous structures as defined herein to the silica / silicon in said aerogel or xerogel.

[0083] In some embodiments, the aerogel or xerogel comprises a molar ratio of carbon to silica of about 0.01 : 1. In some embodiments, the aerogel or xerogel comprises a molar ratio of carbon to silica of about 0.02: 1. In some embodiments, the aerogel or xerogel comprises a molar ratio of carbon to silica of about 0.04: 1. In some embodiments, the aerogel or xerogel comprises a molar ratio of carbon to silica of about 0.08: 1. In some embodiments, the aerogel or xerogel comprises a molar ratio of carbon to silica of about 0.1 : 1. In some embodiments, the aerogel or xerogel comprises a molar ratio of carbon to silica of about 0.2: 1. In some 1 embodiments, the aerogel or xerogel comprises a molar ratio of carbon to silica of about 0.3: 1. In some embodiments, the aerogel or xerogel comprises a molar ratio of carbon to silica of about 0.4: 1. In some embodiments, the aerogel or xerogel comprises a molar ratio of carbon to silica of about 0.5: 1. In some embodiments, the aerogel or xerogel comprises a molar ratio of carbon to silica of about 1 : 1. In some embodiments, the aerogel or xerogel comprises a molar ratio of carbon to silica of about 2: 1. In some embodiments, the aerogel or xerogel comprises a molar ratio of carbon to silica of about 3: 1. In some embodiments, the aerogel or xerogel comprises a molar ratio of carbon to silica larger than about 4: 1. In some preferred embodiments, the aerogel or xerogel comprises a molar ratio of carbon to silica of at least 0.1 : 1 and at most 4: 1. In some embodiments, the carbon groups and / or other carbonaceous structures on the aerogel network may be identified and quantified via the chemical shifts in NMR spectra,13C NMR spectra, and quantitative NMR data of the aerogel specimen. One of ordinary skill in the art would know how to obtain and analyze NMR spectra,13C NMR spectra, and quantitative NMR data.

[0084] In some embodiments, aerogel or xerogel may exhibit a certain hydrophobicity. The term “hydrophobicity”, as used herein, has a well established meaning within the art and is intended to have the meaning as understood in the art. In particular, hydrophobicity can be defined as the property of a material or substance that repels or resists the interaction with water molecules.

[0085] In some embodiments, a surface contact angle may be obtained by placing a water droplet on a flat surface of aerogel or xerogel. In some embodiments, the contact angle may serve as a measure or quantification of the hydrophobicity. In some embodiments, contact angles may be measured using a goniometer according to the standard BS EN 828:2013. In some embodiments, the water contact angle on the aerogel or xerogel surface may be at least 90° and preferably at most 175°. In some embodiments, the water contact angle on the aerogel or xerogel surface may be at least 100° and preferably at most 175°. In some embodiments, the water contact angle on the aerogel or xerogel surface may be at least 125° and preferably atmost 175°. In some embodiments, the water contact angle on the aerogel orxerogel surface may be at least 130° and preferably at most 175°. In some preferred embodiments, the water contact angle on the aerogel or xerogel surface may be at least 140° and preferably at most 175°. In some other embodiments, the water contact angle on the aerogel or xerogel surface may be greater than 150°. In some embodiments, a certain amount of water may be adsorbed by an aerogel or xerogel sample after a certain time when placed in water or at an environment with high relative humidity. In some embodiments, the water vapor uptake may be measured according to the standard BS EN 12086:2013. In some embodiments, the liquid water uptake may be measured according to the standards BS EN 1609:2013, ASTM C1763-14. In some embodiments, the aerogel or xerogel exhibits a 24-h water uptake of at most 30%, preferably ranging from 0.001% to 30%. In some embodiments, the aerogel or xerogel exhibits a 24-h water uptake of at most 20%, preferably ranging from 0.001% to 20%. In some embodiments, the aerogel or xerogel exhibits a 24-h water uptake of at most 15%, preferably ranging from 0.001% to 15%. Yet in some other embodiments, the aerogel or xerogel exhibits a 24-h water uptake of at most 10%%, preferably ranging from 0.001% to 10%.

[0086] In some embodiments, the thermal conductivity of the silica aerogel or xerogel may be at least 1 mW / m-K and at most 40 mW / m-K at 25°C. In some embodiments, the thermal conductivity of the silica aerogel or xerogel may be at least 1 mW / m-K and at most 30 mW / m-K at 25°C. In some preferred embodiments, the thermal conductivity of the silica aerogel or xerogel is at least 1 mW / m-K and at most 25 mW / m-K at 25°C. Yet in some more preferred embodiments, the thermal conductivity of the silica aerogel or xerogel is at least 1 mW / m-K and at most 20 mW / m-K at 25°C. In some embodiments, the thermal conductivity is measured according to standards ASTM C518-17, ASTM C177-19.

[0087] The mass extinction coefficient is a measure of the attenuation of electromagnetic waves by absorption and scattering. In some embodiments, the mass extinction coefficient at a certain wavelength may be a measure to determine the degree of opacification. The mass extinction coefficient of an aerogel may be obtained by dividing the extinction coefficient by the density of the aerogel . In some embodiments, the mass extinction coefficient at a certain wavelength may be a measure to determine and / or compare the degree of opacification.

[0088] The term “opacified”, as used herein, has a well established meaning within the art and is intended to have the meaning as understood in the art. In particular, opacity can be defined as the property of a material that obstructs or prevents the transmission of light. In other words, it describes the degree to which a material is non-transparent or non-translucent, resulting in a lack of clarity or visibility through the material. In some embodiments, the mass extinction coefficient of the aerogel in the wavelength range of 2.3-10 pm may be higher than 5 m2kg'1. In some embodiments, the mass extinction coefficient of the aerogel in the wavelength range of 2.3-10 gm may be higher than 10 m2kg'1. In some preferred embodiments, the mass extinction coefficient of the aerogel in the wavelength range of 2.3-10 pm may be 10-50 m2kg'1. In some more preferred embodiments, the mass extinction coefficient of the aerogel in the wavelength range of 2.3-10 pm may be 30-100 m2kg'1. In most preferred embodiments, the mass extinction coefficient of the aerogel in the wavelength range of 2.3-10 pm is higher than 100 m2kg'1. In some embodiments, the mass extinction coefficient is measured via infrared (IR)-optical investigations with an FTIR spectrometer. One of ordinary skill in the art would know how to obtain (mass) extinctions coefficients.

[0089] Specific capacitance is a measure of the capacity of a material to store electric charge per unit of its mass when an electric potential is applied across the material. In some embodiments, the aerogel or xerogel may exhibit a specific capacitance of 20-100 F g'1, preferably 20-200 F g' more preferably 50-200 F g'1, and most preferably 100-300 F g'1. The electrochemical performance of the aerogel or xerogel comprising specific capacitance may be characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge / discharge (GCD). One of ordinary skill in the art would know how to obtain specific capacitances.

[0090] In the most preferred embodiments, the method for manufacturing a hybrid organic- inorganic silica aerogel or xerogel comprises: polycondensation of a silica source to a silica or organosilica gel, mixing of an organic compound with the silica or organosilica gel, heating of the silica or organosilica gel which comprises the organic compound to at least 200 °C, whereby the organic compound is at least partially pyrolyzed, and simultaneously drying said gel to obtain a hybrid organic-inorganic silica aerogel or xerogel.

[0091] In the most preferred embodiments, the method for manufacturing a hybrid organic- inorganic silica aerogel comprises: polycondensation of a silica source to a silica or organosilica gel, mixing of a polysaccharide with the silica or organosilica gel, heating of the silica or organosilica gel which comprises the polysaccharide to 300 °C, whereby the polysaccharide is at least partially pyrolyzed, and simultaneously supercritically drying said gel. In accordance with these explanations, the invention can also be represented by any of the numbered statements (features) and embodiments of processes, products such as compositions and components, and uses of this invention as set herein below. Each statement and embodiment of the invention so defined may be combined with any other statement and / or embodiment as provided herein unless clearly indicated to the contrary.

[0092] In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features or statements indicated as being preferred or advantageous.

[0093] Hereto, the herein presented invention is also captured by any one or any combination of one or more of the below numbered statements or embodiments, with any other statement and / or embodiment as set out herein. In these statements, the wording “The [subject] according to statement [number], wherein...” or “The [subject] according to any one of statements [numbers], wherein. . .” also discloses and may be replaced by the simple wording “In certain embodiments...”.

[0094] 1. A method for manufacturing a hybrid organic-inorganic silica aerogel or xerogel, comprising heating a silica or organosilica gel which comprises an organic compound to at least 200 °C, whereby the organic compound is at least partially pyrolyzed, and drying the gel.

[0095] 2. A method for manufacturing a hybrid organic-inorganic silica aerogel or xerogel, comprising heating a silica or organosilica gel which comprises an organic compound to at least 200 °C, whereby the organic compound is at least partially pyrolyzed, and supercritically drying the gel.

[0096] 3. A method for manufacturing a hybrid organic-inorganic silica aerogel or xerogel, the method comprising heating a silica or organosilica gel, which comprises an organic compound, to at least 200 °C; whereby the heating comprises at least partially pyrolyzing the organic compound, and drying the gel, wherein the at least partially pyrolyzing of the organic compound and drying of the silica or organosilica gel are part of the same step or the drying is subsequent to the pyrolyzing; and wherein the organic compound is a bio-monomer, bio-oligomer, synthetic polymer, biopolymer, or a mixture thereof.

[0097] 4. A method for manufacturing a hybrid organic-inorganic silica aerogel or xerogel, the method comprising heating a silica or organosilica gel, which comprises an organic compound, to at least 200 °C; whereby the heating comprises at least partially pyrolyzing the organic compound, and drying the gel, wherein the at least partially pyrolyzing of the organic compound and drying of the silica or organosilica gel are part of the same step or the drying is subsequent to the pyrolyzing; and wherein the organic compound is a bio-monomer, bio-oligomer, biopolymer, or a mixture thereof.

[0098] 5. The method of any of statements 1 to 4, wherein the silica or organosilica gel comprises a silica or organosilica network, a pore liquid, and the organic compound.

[0099] 6. The method of any of statements 1 to 5, wherein the silica or organosilica gel comprises or has been prepared using one or more alkoxysilanes, silicon alkoxides, alkali silicates, waterglass, sodium silicate, potassium silicate, lithium silicate, metasilicates, organosilanes, solutions containing silicon adducts, and mixtures thereof.

[0100] 7. The method of any of statements 1 to 6, wherein the silica or organosilica gel is modified with a hydroxyl-containing organic molecule.

[0101] 8. The method of any of statements 1 to 7, wherein the hydroxyl-containing organic molecule comprises an alcohol, optionally wherein the alcohol is an alkyl alcohol, such as a Ci-Cis alkyl alcohol, preferably a C1-C5 alkyl alcohol.

[0102] 9. The method of any of statements 1 to 8, wherein the hydroxyl-containing organic molecule comprises a carboxylic acid, preferably a fatty acid, and more preferably a fatty acid comprising 13 to 26 carbon atoms, such as from 13 to 20 carbon atoms.

[0103] 10. The method of any of statements 1 to 9, wherein the hydroxyl-containing organic molecule comprises an alcohol, and wherein the alcohol is a fatty alcohol.

[0104] 11. The method of any of statements 1 to 10, wherein the hydroxyl-containing organic molecule comprises an alcohol selected from the group comprising methanol, ethanol, isopropanol, n-propanol, tert-butanol, sec-butanol, n-butanol, and mixtures thereof, and / or a fatty acid.

[0105] 12. The method of any of statements 1 to 11, wherein the heating of the silica or organosilica gel is to at least 240°C, preferably to at least 300°C.

[0106] 13. The method of any of statements 1 to 12, wherein the heating of the silica or organosilica gel is to no more than 400 °C, such as no more than 390°C, no more than 380°C, no more than 370°C, no more than 360°C, no more than 350°C, or no more than 340°C.

[0107] 14. The method of any of statements 1 to 13, wherein the heating and drying of the silica or organosilica gel are part of the same step, for example they take place at least partly concurrently. 15. The method of statement 14, comprising supercritically drying the silica or organosilica gel by heating the silica or organosilica gel to at least 200°C, preferably to at least 240°C, more preferably at least 300 °C, and optionally to no more than 400°C, such as no more than 390°C, no more than 380°C, no more than 370°C, no more than 360°C, no more than 350°C, or no more than 340°C.

[0108] 16. The method of any of statements 14 or 15, wherein the supercritical drying is performed at a pressure of at least 1 MPa and at most 20 MPa, preferably at least 1 MPa and at most 10 MPa.

[0109] 17. The method of statement 16, comprising subcritically drying the silica or organosilica gel by heating the silica or organosilica gel to at least 200°C, preferably to at least 240°C, more preferably at least 300 °C, and optionally to no more than 400°C.

[0110] 18. The method of any one of statements 1 to 17, wherein the heating is performed for at most 2 hours, or at most 1 hour, or at most 55 minutes, or at most 50 minutes, or at most 45 minutes, or at most 40 minutes, or at most 35 minutes, or at most 30 minutes.

[0111] 19. The method of any one of statements 1 to 18, wherein the heating is performed for at least 1 minute, or at least 2 minutes, or at least 3 minutes, or at least 4 minutes, or at least 5 minutes. 0. The method of any of statements 1 to 19, wherein the heating and drying of the silica or organosilica gel are separate steps, i.e., wherein the gel is first heated to initiate the at least partial pyrolysis of the organic compound, and the gel with the at least partially pyrolyzed organic compound is subsequently dried. 1. The method of statement 20, comprising drying the silica or organosilica gel under ambient pressure. 2. The method of any of statements 20 or 21, comprising drying the silica or organosilica gel under ambient pressure by heating the silica or organosilica gel to at most 200°C, such as at most 160 °C, such as at most 150 °C, such as at most 130 °C, such as at most 100 °C, such as at most 85 °C, such as at most 65 °C, such as at most 45 °C, and such as at most 30 °C. 3. The method of any of statements 20 to 22, wherein the pore liquid of the silica or organosilica gel is a comparatively higher surface tension liquid, and is exchanged for a comparatively lower surface tension liquid prior to drying. 4. The method of any of statements 23, wherein the comparatively lower surface tension liquid is selected from the group consisting of: liquid CO2, alcohol, an alkane, or ether solvent, preferably an alkyl alcohol, an alkane, or alkyl ether solvent, more preferably a Ci-isalkyl alcohol, a Ci-isalkane, or Ci-isalkyl ether solvent.

[0112] 25. The method of any of statements 1 to 24, wherein the organic compound is a monomer, an oligomer, a polymer, such as a biopolymer or a synthetic polymer, or a mixture thereof.

[0113] 26. The method of any of statements 1 to 25, wherein the monomer or oligomer is selected from the group consisting of: a monosaccharide, an oligosaccharide, an amino acid, an oligopeptide, a glucosinolate, a nucleotide, an oligonucleotide, a phenol, tryptophol, indole-3 -carbinol, serotonin, a hydroxy fatty acid, and mixtures thereof.

[0114] 27. The method of statement 26, wherein the monosaccharide is selected from the group consisting of: glucose, fructose, galactose, deoxyribose, dihydroxyacetone (glycerone), glyceraldehyde, erythrose, threose, ribose, arabinose, xylose, lyxose, allose, altrose, mannose, idose, talose, mannoheptulose, sedoheptulose, and mixtures thereof.

[0115] 28. The method of any of statements 26 or 27, wherein the monosaccharide comprises furanose, and wherein the furanose is selected from the group consisting of: glucofuranose, fructofuranose, galactofuranose, deoxyribofuranose, erythrofuranose, threofuranose, ribofuranose, arabinofuranose, xylofuranose, lyxofuranose, allofuranose, altrofuranose, mannofuranose, idofuranose, talofuranose, and mixtures thereof.

[0116] 29. The method of any of statements 26 to 28, wherein the monosaccharide comprises pyranose, and wherein the pyranose is selected from the group consisting of: glucopyranose, fructopyranose, galactopyranose, deoxyribopyranose, erythropyranose, threopyranose, ribopyranose, arabinopyranose, xylopyranose, lyxopyranose, allopyranose, altropyranose, mannopyranose, idopyranose, talopyranose, and mixtures thereof.

[0117] 30. The method of any of statements 26 to 29, wherein the monosaccharide comprises a monosaccharide derivative, and wherein the monosaccharide derivative is selected from the group consisting of: amino sugar, sulfosugar, sugar alcohol, sugar acid, and mixtures thereof.

[0118] 31. The method of statement 30, wherein the amino sugar is selected from the group consisting of: galactosamine, glucosamine, sialic acid, N-acetylglucosamine, and mixtures thereof.

[0119] 32. The method of statement 30, wherein the sulfosugar comprises sulfoquinovose.

[0120] 33. The method of statement 30, wherein the sugar alcohol comprises mannitol. 34. The method of statement 30, wherein the sugar acid is selected from the group consisting of: ascorbic acid, glucuronic acid, and mixtures thereof.

[0121] 35. The method of statement 26, wherein the oligosaccharide is selected from the group consisting of: disaccharide, trisaccharide, tetrasaccharide, and mixtures thereof.

[0122] 36. The method of statement 26, wherein the oligosaccharide comprises between 2 and 10 monosaccharide units, and preferably wherein the oligosaccharide is selected from the group consisting of: disaccharide, trisaccharide, tetrasaccharide, and mixtures thereof.

[0123] 37. The method of statement 35 or 36, wherein the disaccharide is selected from the group consisting of: cellobiose, sucrose, lactose, maltose, trehalose, chitobiose, and mixtures thereof.

[0124] 38. The method of statement 35 or 36, wherein the trisaccharide is selected from the group consisting of: cellotriose, maltotriose, nigerotriose, melezitose, maltotriulose, raffinose, kestose, and mixtures thereof.

[0125] 39. The method of statement 35 or 36, wherein the tetrasaccharide is selected from the group consisting of: cellotetraose, lychnose, maltotetraose, nigerotetraose, nystose, sesamose, stachyose, and mixtures thereof.

[0126] 40. The method of any of statements 26 to 39, wherein the biopolymer is selected from the group consisting of: a polysaccharide, a polypeptide, a polynucleotide, a tannin, melanin, cutin, cutan, latex, rubber, and mixtures thereof.

[0127] 41. The method of any of statements 1 to 40, wherein the organic compound is a monosaccharide, an oligosaccharide, or a polysaccharide, such as wherein the polysaccharide is selected from the group consisting of: cellulose, nanocellulose, nanofibrillated cellulose, hemicellulose, xylan, lignin, lignosulfonate, chitin, pectin, arabinoxylan, starch, glycogen, inulin, xanthan gum, guar gum, agar, agarose, alginate, chitosan, heparin, and mixtures thereof.

[0128] 42. The method of statement 41, wherein the cellulose is selected from the group consisting of: microcrystalline cellulose, microbial cellulose, nanocellulose, nanofibrillated cellulose, cellulose nanofibers, nanocrystalline cellulose, cellulose nanocrystals, bacterial nanocellulose, and mixtures thereof.

[0129] 43. The method of any of statements 41 or 42, wherein the nanofibrillated cellulose comprises cellulose particles having an elongated form, an aspect ratio larger than 1, an average length in the range of 15 to 900 nm, preferably in the range of 50 to 700 nm, more preferably in the range of 70 to 700 nm; and an average thickness in the range of 3 to 200 nm, preferably in the range of 5 to 100 nm, more preferably in the range of 5 to 30 nm.

[0130] 44. The method of statement 41, wherein the hemicellulose is selected from the group consisting of: xylose, arabinose, mannose, galactose, deoxy sugar rhamnose, and mixtures thereof; and optionally comprises glucuronic and galacturonic acid.

[0131] 45. The method of statement 41, wherein the lignin is selected from the group consisting of: kraft lignin, sulfonated lignin, soda lignin, and mixtures thereof.

[0132] 46. The method of any of statements 26 to 45, wherein the synthetic polymer is selected from the group consisting of: polyamide, polyimide, polyacrylamide, polyacrylate, polyacrylonitrile, polycyanurate, polyurea, polyurethane, polyisocyanurate, polyaramid, polyester, polyamine, polycarbonate, polyether, polyol, polyvinyl alcohol, polyvinyl alcohol dialdehyde, polyvinyl ester, polyaldehyde, phenolic resin, resorcinol formaldehyde (polymer / resin), phenol formaldehyde (polymer / resin), melamine formaldehyde (polymer / resin), cresol formaldehyde (polymer / resin), phenol furfuryl alcohol, polyepoxide (epoxy), and mixtures thereof.

[0133] 47. The method of any of statements 1 to 46, wherein the organic compound is substantially homogeneously distributed in the silica or organosilica gel, optionally wherein the organic compound is introduced into the silica or organosilica gel at the solution or sol state.

[0134] 48. The method of any of statements 1 to 47, wherein the weight percentage of the organic compound in the silica or organosilica gel is 0.001-20 wt%, preferably 0.01-10 wt%, more preferably 0.05-5 wt%, such as wherein the organic compound is introduced into the silica or organosilica gel at the solution or sol state at 0.001-20 wt%, preferably 0.01- 10 wt%, more preferably 0.05-5 wt% of the solution or sol.

[0135] 49. The method of any of statements 5 to 48, wherein the pore liquid comprises liquid CO2, alcohol, alkane, or ether solvent, preferably an alkyl alcohol, an alkane, or alkyl ether solvent, more preferably a Ci-isalkyl alcohol, a Ci-isalkane, or Ci-isalkyl ether solvent.

[0136] 50. The method of any of statements 1 to 49, wherein the heating and / or drying of the gel is performed in a vessel, such as an autoclave or a plug flow reactor, and optionally in the presence of microwave radiation.

[0137] 51. The method of statement 50, wherein microwave radiation comprises: a. a frequency of radiation of at least 0.5 GHz and at most 5 GHz; and / or b. a power of radiation of at least 200 W and of at most 700 W, preferably of at least 400 W and of at most 600 W.

[0138] 52. The method of any of statements 1 to 51, wherein the heating of the gel is performed in the absence of air.

[0139] 53. The method of any of statements 1 to 52, comprising the heating of the gel is performed under inert atmosphere, optionally the inert atmosphere is achieved by using a noble gas.

[0140] 54. The method of any of statements 1 to 53, wherein the heating of the gel is performed under gaseous carbon atmosphere, such as wherein the gaseous carbon atmosphere is selected from the group consisting of: carbon dioxide, methane, ethane, propane, and mixtures thereof.

[0141] 55. The method of any of statements 1 to 54, wherein the at least partial pyrolysis is performed in the presence of a catalyst, optionally in the presence of a zeolite catalyst.

[0142] 56. The method of any of statements 1 to 55, wherein the at least partial pyrolysis comprises carbonization, graphitization, coalification, aromatization, charring, dehydrogenation, dehydration, polycondensation, depolymerization, volatilization, and / or combustion.

[0143] 57. The method of any of statements 1 to 56, wherein the silica or organosilica gel is completely pyrolyzed at a temperature of at least 500 °C, such as of at least 550 °C, such as of at least 600 °C, of at least 650 °C, such as of at least 700 °C.

[0144] 58. The method of statement 57, wherein the aerogel or xerogel obtained after drying has a specific capacitance of 20-100 F g’1, preferably 20-200 F g' more preferably 50-200 F g’1, and most preferably 100-300 F g’1.

[0145] 59. The method of any of statements 1 to 58, wherein the at least partial pyrolysis of the organic compound forms a carbonaceous structure, and preferably wherein the carbonaceous structure provides hydrophobicity and opacification of the hybrid organic- inorganic silica aerogel or xerogel.

[0146] 60. The method of any of statements 1 to 59, wherein: a. the aerogel or xerogel exhibits a surface contact angle of greater than 100°; b. the aerogel or xerogel exhibits a 24-h water uptake of less than 15%; c. the thermal conductivity of the aerogel or xerogel is less than 25 mW / m-K at 25°C; and / or d. the mass extinction coefficient of the aerogel or xerogel in the wavelength range of 2.3-10 pm is 10-30 m2kg' preferably 10-50 m2kg'1, more preferably 30-100 m2kg'1, and most preferably higher than 100 m2kg'1.

[0147] 61. The method of any of statements 1 to 60, wherein the aerogel or xerogel exhibits a surface contact angle greater than 125 °, preferably greater than 130 °, more preferably greater than 140 °, most preferably greater than 150 °.

[0148] 62. The method of any of statements 1 to 61, wherein the organic compound is a hydrophilic organic compound and the silica or organosilica gel comprising the organic compound displays a surface contact angle less than 90 °, and the aerogel or xerogel obtained therefrom is hydrophobic with a surface contact angle greater than 140 °.

[0149] 63. The method of any of statements 1 to 62, wherein the aerogel or xerogel exhibits a skeletal density of less than 5 g cc'1, preferably less than 4 g cc'1, more preferably 3 g cc' 1 and most preferably 1.6 g cc'1.

[0150] 64. The method of any of statements 1 to 63, wherein the aerogel or xerogel exhibits an envelope density of at least about 0.05 g / cc and at most about 0.7 g / cc, preferably at least about 0.05 g / cc and at most about 0.5 g / cc, more preferably at least about 0.05 g / cc and at most about 0.3 g / cc and most preferably at least about 0.05 g / cc and at most about 0.2 g / cc.

[0151] 65. The method of any of statements 1 to 64, wherein the aerogel or xerogel exhibits a porosity of at least 50 %, preferably at least 60%, preferably at least 70%, more preferably at least 80%, most preferably at least 90%.

[0152] 66. The method of any of statements 1 to 65, wherein the aerogel or xerogel exhibits a specific surface area of at least 400 m2g'1and at most 1200 m2g'1.

[0153] 67. The method of any of statements 1 to 66, wherein the aerogel or xerogel exhibits a pore size distribution of at least 2 nm to at most 50 nm.

[0154] 68. A hybrid organic-inorganic silica aerogel or xerogel, obtainable or obtained by the method of any one of previous statements 1 to 67.

[0155] 69. A hybrid organic-inorganic silica aerogel or xerogel, obtainable or obtained by the method of any one of claims 1 to 68, having

[0156] - a specific capacitance of 20-100 F g'1, preferably 50-200 F g'1, preferably 100-300 F g'1; and / or - a mass extinction coefficient in the wavelength range of 2.3-10 gm of 10-50 m2kg'1, preferably 30-100 m2kg'1, preferably higher than 100 m2kg'1; optionally, a surface contact angle of greater than 100°;optionally, a thermal conductivity of less than 25 mW / m-K at 25°C; optionally, a 24-h water uptake of less than 15%.

[0157] While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as follows in the spirit and scope of the appended claims.

[0158] The herein disclosed aspects and embodiments of the invention are further supported by the following non-limiting examples.

[0159] EXAMPLES

[0160] EXAMPLE 1

[0161] An organosilica gel comprising an organic compound was prepared by adding to a first solution comprising 150 g tetramethoxysilane (TMOS) and 120 g of methanol, a second solution comprising 70 g of 0.3 M aqueous ammonia, 120 g of methanol, and 100 g of a 3 wt% nanocellulose water-based solution under constant stirring for 5 min. Gelation took place in about 15 min. The resulting gel was opaque white and aged for 24 hours and was subsequently crushed into smaller pieces of 5 to 10 mm and solvent exchanged in fresh methanol for 24 hours at 50 °C. The solvent exchanged gel pieces were then placed in a stainless steel autoclave of 750 mL inner volume to which fresh methanol was added until the inner volume of the vessel was filled for about 80%. After closing the autoclave, an electric heating mantle increased the temperature inside the vessel while the pressure increased automatically and was kept at a maximum of 80 bar by repeatedly opening and closing a release valve. Heating continued until a temperature of 300°C was reached inside the vessel, after which the temperature was set to remain constant for 5 to 10 minutes to induce pyrolysis and drying of the gel. Subsequently, the release valve was opened such that the pressure dropped isothermally from 80 bar to atmospheric pressure in 1 hour. The autoclave was then allowed to cool down for 3 hours to 25 °C. When the autoclave was cooled down to 25 °C, the formed aerogel pieces were removed from the vessel for analysis. At least some of the aerogel pieces were monolithic structures with a maximum dimension larger than 10 cm. The aerogel pieces were substantially crack-free and uniform, had practically the same shape and size as the original wet gel pieces, but were now opacified to an orange-brown color, while having an envelope and skeletal density of about 0.092 g / cc and 1.69 g / cc, respectively, a BET surface area of about 580 m2 / g, a mass extinction coefficient of about 55 m2 / kg, and being superhydrophobic (contact angle of about 145°, using a goniometer according to the standard BS EN 828:2013). A thermal conductivity of 17 mW / m-K was measured using a Netzch heat flow meter (ASTM C518-17).

[0162] EXAMPLE 2

[0163] A silica gel comprising an organic compound was prepared by adding, under continuous stirring to a 400 mL aqueous silicic acid solution comprising 8 wt% silica and having a pH around 2.2, 15 g of pectin powder (with >74% galacturonic acid), followed by the addition of 1 M ammonia in water solution until a pH of 3.6 was obtained. The as-obtained sol was then heated to 50°C for one hour in order to obtain a stiff gel. The gel had an opalescent yellow-orange appearance and become more opaque after aging for 24 hours, after which the gel was broken into smaller pieces of 5 to 10 mm and solvent exchanged in a solution having a 25 / 75 ethanol-water volume ratio for 24 hours at 50°C, then in a solution having a 50 / 50 ethanol-water volume ratio for 24 hours at 50°C, followed by a solution having a 75 / 25 ethanol-water volume ratio for 24 hours at 50°C, and finally in a solution of 98% ethanol for 24 hours at 50°C. The solvent exchanged gel particles were then dried and pyrolyzed according to the procedure described in Example 1 to obtain aerogel material. The aerogel pieces were substantially crack-free and uniform, had practically the same shape as the original wet gel pieces, but had shrunken about 10% in volume and now appeared opaque beige-grey in color, while the inside was dark brown. The aerogel had an envelope and skeletal density of about 0.090 g / cc and 1.66 g / cc, respectively, a BET surface area of about 620 m2 / g, a mass extinction coefficient of about 45 m2 / kg, and was superhydrophobic (contact angle of about 142°, using a goniometer according to the standard BS EN 828:2013). A thermal conductivity of 16 mW / m-K was measured using a Netzch heat flow meter (ASTM C518-17). EXAMPLE 3

[0164] An organosilica gel comprising an organic compound was prepared by adding to a first solution comprising 150 g tetramethoxysilane (TMOS) and 120 g of methanol, a second solution comprising 70 g of 0.3 M aqueous ammonia, 120 g of methanol, and 50 g of an aqueous 55 wt% sodium lignosulfonate solution under constant stirring for 5 min. Gelation took place in about 15 min. The resulting gel had a dark red-brown color and aged for 24 hours and was subsequently crushed into smaller pieces of 5 to 10 mm and solvent exchanged in fresh methanol for 24 hours at 50 °C. The solvent exchanged gel particles were then dried and pyrolyzed according to the procedure described in Example 1 to obtain aerogel material. The aerogel pieces were substantially crack-free and uniform, had practically the same shape and size as the original wet gel pieces, but were now opacified to a brown-grey color, while having an envelope and skeletal density of about 0.093 g / cc and 1.62 g / cc, respectively, a BET surface area of about 560 m2 / g, a mass extinction coefficient of about 60 m2 / kg, and being superhydrophobic (contact angle of about 141°, using a goniometer according to the standard BS EN 828:2013). A thermal conductivity of 17 mW / m-K was measured using a Netzch heat flow meter (ASTM C518-17).

[0165] EXAMPLE 4

[0166] An organosilica gel comprising an organic compound was prepared by first preparing a solution comprising 150 g tetramethoxysilane (TMOS) and 120 g of methanol. A second solution comprising 70 g of 0.3 M aqueous ammonia, 100 g of methanol, and 15 g of kraft lignin powder was then prepared and subseqently added to the first solution under constant stirring for 5 min. Gelation took place in about 15 min. The resulting gel had a dark red- brown color. After aging for 24 hours, the gel was crushed into smaller pieces of 5 to 10 mm and solvent exchanged in fresh methanol for 24 hours at 50 °C. The solvent exchanged gel particles were then dried and pyrolyzed according to the procedure described in Example 1 to obtain aerogel material. The aerogel pieces were substantially crack-free and uniform, had practically the same shape and size as the original wet gel pieces, but were now opacified to a brown color, while having an envelope and skeletal density of about 0.098 g / cc and 1.67 g / cc, respectively, a BET surface area of about 570 m2 / g, a mass extinction coefficient of about 60 m2 / kg, and being superhydrophobic (contact angle of about 146°, using a goniometer according to the standard BS EN 828:2013). A thermal conductivity of 18 mW / m-K was measured using a Netzch heat flow meter (ASTM C518-17). EXAMPLE 5

[0167] An organosilica gel comprising an organic compound was prepared by first preparing a solution comprising 150 g tetramethoxysilane (TMOS) and 120 g of isopropanol. A second solution comprising 70 g of 0.3 M aqueous ammonia, 120 g of isopropanol, and 5 g of chitin powder was then prepared and subsequently added to the first solution under constant stirring for 5 min. Gelation took place in about 15 min. The resulting gel had a white color. After aging for 24 hours, the gel was crushed into smaller pieces of 5 to 10 mm and solvent exchanged in fresh isopropanol for 24 hours at 50 °C. The solvent exchanged gel particles were then dried and pyrolyzed according to the procedure described in Example 1 to obtain aerogel material. The aerogel pieces were substantially crack-free and uniform, had practically the same shape and size as the original wet gel pieces, but were now opacified to a dark blue-grey color, while having an envelope and skeletal density of about 0.093 g / cc and 1.68 g / cc, respectivley, a BET surface area of about 590 m2 / g, a mass extinction coefficient of about 55 m2 / kg, and being superhydrophobic (contact angle of about 142°, using a goniometer according to the standard BS EN 828:2013). A thermal conductivity of 17 mW / m-K was measured using a Netzch heat flow meter (ASTM C518-17).

[0168] EXAMPLE 6

[0169] An organosilica gel comprising an organic compound was prepared by adding to a first solution comprising 150 g tetramethoxysilane (TMOS) and 120 g of methanol, a second solution comprising 70 g of 0.3 M aqueous ammonia, 120 g of methanol, and 50 g of the inside contents of a chicken eggunder constant stirring for 5 min. Gelation took place in about 15 min. The resulting gel had a yellow color and aged for 24 hours and was subsequently crushed into smaller pieces of 5 to 10 mm and solvent exchanged in fresh methanol for 24 hours at 50 °C. The solvent exchanged gel particles were then dried and pyrolyzed according to the procedure described in Example 1 to obtain aerogel material. The aerogel pieces were substantially crack-free and uniform, had practically the same shape and size as the original wet gel pieces, but were now opacified to a brown-grey color, while having an envelope and skeletal density of about 0.104 g / cc and 1.62 g / cc, respectively, a BET surface area of about 630 m2 / g, a mass extinction coefficient of about 55 m2 / kg, and being superhydrophobic (contact angle of about 144°, using a goniometer according to the standard BS EN 828:2013). A thermal conductivity of 17 mW / m-K was measured using a Netzch heat flow meter (ASTM C518-17). EXAMPLE 7

[0170] A silica gel comprising an organic compound was prepared by first dissolving 80 g of shredded orange peel particles in 240 g of a 31 % aqueous sulfuric acid solution at a temperature of 70 °C under stirring at 400 rpm for 4 hours. Filtering the as-obtained slurry to remove undissolved peel remains and to obtain a clear red-brown solution. 56 g of the aforementioned solution was then cooled to 0 °C after which a solution consisting of 132 g of an aqueous solution of sodium silicate (waterglass, consisting of 39-40 wt% silicates and about 25.8-28.5 wt% SiCh with a SiCh / NfeO ratio of 3.3) and 106 g of deionized water was gradually added under vigorous stirring while maintaining the temperature of the solution under 5 °C. Then 111 g of ethanol was added and the stirring was stopped for salts to precipitate down. After 30 minutes the salts were removed from the silica sol via centrifugation. 80 g of a 1 M aqueous ammonia solution was then added to the silica sol in a beaker under constant stirring at 300 rpm until a pH of 4 was reached. The beaker was sealed and put in an oven at 60 °C for 30 min. A translucent orange stiff gel was obtained and aged for 24 hours after which it was broken into pieces of 5 to 10 mm and solvent exchanged in a solution having a 60 / 40 ethanol-water volume ratio for 24 hours at 50 °C, then in a solution having a 80 / 20 ethanol-water volume ratio for 24 hours at 50°C, and finally in a solution of 98% ethanol for 24 hours at 50°C. The solvent exchanged gel particles were then dried and pyrolyzed according to the procedure described in Example 1 to obtain aerogel material. The aerogel pieces were substantially crack-free and uniform, had practically the same shape as the original wet gel pieces, but had shrunken about 15% in volume and now appeared opalescent beige-yellow in color. The aerogel was found to have an envelope and skeletal density of about 0.125 g / cc and 1.67 g / cc, respectively, a BET surface area of about 620 m2 / g, a mass extinction coefficient of about 45 m2 / kg, to be superhydrophobic with a contact angle of 125° (using a goniometer according to the standard BS EN 828:2013), and to have a thermal conductivity of 19 mW / m-K as measured using a Netzch heat flow meter (ASTM C518-17).

[0171] EXAMPLE 8

[0172] A silica gel comprising an organic compound was prepared by first cooling 56 g of a 25% aqueous sulfuric acid solution to 0 °C after which a solution consisting of 132 g of an aqueous solution of sodium silicate (waterglass, consisting of 39-40 % silicates and about 25.8-28.5 wt% SiCh with a SiO2:Na2O ratio of 3.3) and 106 g of deionized water was gradually added under vigorous stirring while maintaining the temperature of the solution under 5 °C. Then 111 g of ethanol was added and the stirring was stopped for salts to precipitate down. After 30 minutes the salts were removed from the silica sol via centrifugation. 30 g of commercial brown sugar (sucrose sugar containing sugarcane molasses) was added to the sol under stirring at 300 rpm until all the sugar had dissolved and a red-brown translucent liquid was obtained. 80 g of a 1 M aqueous ammonia solution was then added to the silica sol in a beaker under constant stirring at 300 rpm until a pH of 4 was reached. The beaker was sealed and put in an oven at 60°C for 30 min. A translucent red-brown stiff gel was obtained and aged for 24 hours after which it was broken into pieces of 5 to 10 mm and solvent exchanged in a solution having a 60 / 40 ethanol-water volume ratio for 24 hours at 50°C, then in a solution having a 80 / 20 ethanol-water volume ratio for 24 hours at 50°C, and finally in a solution of 98% ethanol for 24 hours at 50°C. The solvent exchanged gel particles were then dried and pyrolyzed according to the procedure described in Example 1 to obtain aerogel material. The aerogel pieces were substantially crack-free and uniform, had practically the same shape as the original wet gel pieces, and now appeared opalescent orange-brown in color. The aerogel was found to have an envelope and skeletal density of about 0.095 g / cc and 1.6 g / cc, respectively, a BET surface area of about 640 m2 / g, a mass extinction coefficient of about 50 m2 / kg, to be superhydrophobic with a contact angle of 125°, and to have a thermal conductivity of 17 mW / m-K as measured using a Netzch heat flow meter (ASTM C518-17).

[0173] EXAMPLE 9

[0174] A silica gel comprising an organic compound was prepared by first cooling 56 g of a 25% aqueous sulfuric acid solution to 0 °C after which a solution consisting of 132 g of an aqueous solution of sodium silicate (waterglass, consisting of 39-40 wt% silicates and about 25.8- 28.5 wt% SiCh with a SiO2:Na2O ratio of 3.3) and 106 g of deionized water was gradually added under vigorous stirring while maintaining the temperature of the solution under 5 °C. Then 111 g of ethanol was added and the stirring was stopped for salts to precipitate down. After 30 minutes the salts were removed from the silica sol via centrifugation. 30 g of an aqueous solution of 55 wt% magnesium lignosulfonate was added to the sol under stirring at 300 rpm. 80 g of a 1 M aqueous ammonia solution was then added to the silica sol in a beaker under constant stirring at 300 rpm until a pH of 4 was reached. The beaker was sealed and put in an oven at 60°C for 30 min. A translucent red-brown stiff gel was obtained and aged for 24 hours after which it was broken into pieces of 5 to 10 mm and solvent exchanged in a solution having a 60 / 40 ethanol-water volume ratio for 24 hours at 50°C, then in a solution having a 80 / 20 ethanol-water volume ratio for 24 hours at 50°C, and finally in a solution of 98% ethanol for 24 hours at 50°C. The solvent exchanged gel particles were then dried and pyrolyzed according to the procedure described in Example 1 to obtain aerogel material. The aerogel pieces were substantially crack-free and uniform, had practically the same shape as the original wet gel pieces, without noticeable shrinkage in volume and now appeared blue-grey in color. The aerogel was found to have an envelope and skeletal density of about 0.07 g / cc and 1.64 g / cc, respectively, a BET surface area of about 1100 m2 / g, a mass extinction coefficient of about 55 m2 / kg, to be superhydrophobic with a contact angle of 120°, and to have a thermal conductivity of 16 mW / m-K as measured using a Netzch heat flow meter (ASTM C518-17).

[0175] COMPARATIVE EXAMPLE 1

[0176] An organosilica gel comprising no organic compound was prepared by adding to a first solution comprising 150 g tetramethoxysilane (TMOS) and 120 g of methanol, a second solution comprising 70 g of 0.3 M aqueous ammonia and 120 g of methanol under constant stirring for 5 min. Gelation took place in about 15 min. The resulting gel was transparent and aged for 24 hours and was subsequently crushed into smaller pieces of 5 to 10 mm and solvent exchanged in fresh methanol for 24 hours at 50 °C. The solvent exchanged gel particles were then dried according to the procedure described in Example 1 to obtain aerogel material. The aerogel pieces had practically the same shape and size as the original wet gel pieces, but with some cracks, and remained transparent, while having an envelope and skeletal density of about 0.115 g / cc and 2.2 g / cc, respectively, a BET surface area of about 750 m2 / g, and being hydrophilic (water droplets got instantly adsorbed and aerogel pieces sank to the bottom of a beaker filled with water after 30 seconds). A thermal conductivity of 19 mW / m-K was measured using a Netzch heat flow meter (ASTM C518-17).

[0177] COMPARATIVE EXAMPLE 2

[0178] A silica gel comprising no organic compound was prepared by adding, under continuous stirring to a 350 mL aqueous silicic acid solution comprising 8 wt% silica and having a pH around 2.2, 1 M of ammonia in water solution until a pH of 3.6 was obtained. The as-obtained sol was then heated to 50°C for one hour in order to obtain a stiff gel. The gel had a blueish translucent appearance and became slightly more opaque after aging for 24 hours, after which the gel was broken into smaller pieces of 5 to 10 mm and solvent exchanged in a solution having a 25 / 75 ethanol-water volume ratio for 24 hours at 50°C, then in a solution having a 50 / 50 ethanol-water volume ratio for 24 hours at 50°C, followed by a solution having a 75 / 25 ethanol-water volume ratio for 24 hours at 50°C, and finally in a solution of 98% ethanol for 24 hours at 50°C. The solvent exchanged gel particles were then dried according to the procedure described in Example 1 to obtain aerogel material. The aerogel pieces had practically the same shape as the original wet gel pieces, but had shrunken about 30% in volume, had cracks, and now appeared opaque white in color. The aerogel had an envelope and skeletal density of about 0.135 g / cc and 2.2 g / cc, respectively, a BET surface area of about 480 m2 / g, and was hydrophilic (water droplets got instantly adsorbed and aerogel pieces sank to the bottom of a beaker filled with water in a matter of seconds). A thermal conductivity of 25 mW / m-K was measured using a Netzch heat flow meter (ASTM C518-17).

Claims

CLAIMS1. A method for manufacturing a hybrid organic-inorganic silica aerogel or xerogel, the method comprising heating a silica or organosilica gel, which comprises an organic compound, to at least 200 °C; whereby the heating comprises at least partially pyrolyzing the organic compound, and drying the gel, wherein the at least partially pyrolyzing of the organic compound and drying of the silica or organosilica gel are part of the same step or the drying is subsequent to the pyrolyzing; and wherein the organic compound is a bio-monomer, bio-oligomer, synthetic polymer, biopolymer, or a mixture thereof.

2. The method of claim 1, wherein the silica or organosilica gel comprises a silica or organosilica network, a pore liquid, and the organic compound.

3. The method of any one of claims 1 -2, wherein the heating of the silica or organosilica gel is to at least 240 °C, preferably to at least 300 °C.

4. The method of any one of claims 1-3, wherein the heating of the silica or organosilica gel is to no more than 400 °C.

5. The method of any one of claims 1-4, wherein the heating and drying of the silica or organosilica gel are part of the same step.

6. The method of claim 5, comprising supercritically drying the silica or organosilica gel by heating the silica or organosilica gel to at least 200 °C, preferably to at least 240 °C, more preferably at least 300 °C, and optionally to no more than 400 °C.

7. The method of any one of claims 1-6, wherein the silica or organosilica gel comprises or has been prepared using one or more alkoxysilanes, silicon alkoxides, alkali silicates, waterglass, sodium silicate, potassium silicate, lithium silicate, metasilicates, organosilanes, solutions containing silicon adducts, or mixtures thereof.

8. The method of any one of claims 1-7, wherein the bio-monomer or bio-oligomer is selected from the group consisting of: a monosaccharide, an oligosaccharide, an amino acid, an oligopeptide, a glucosinolate, a nucleotide, an oligonucleotide, a phenol, tryptophol, indole-3 -carbinol, serotonin, a hydroxy fatty acid, and mixtures thereof.

9. The method of claim 8, wherein the monosaccharide is selected from the group consisting of: glucose, fructose, galactose, deoxyribose, dihydroxyacetone (glycerone), glyceraldehyde, erythrose, threose, ribose, arabinose, xylose, lyxose, allose, altrose, mannose, idose, talose, mannoheptulose, sedoheptulose, and mixtures thereof.

10. The method of claim 8, wherein the oligosaccharide comprises between 2 and 10 monosaccharide units, and preferably wherein the oligosaccharide is selected from the group consisting of: disaccharide, trisaccharide, tetrasaccharide, and mixtures thereof.

11. The method of any one of claims 1-10, wherein the biopolymer is selected from the group consisting of: a polysaccharide, a polypeptide, a polynucleotide, a tannin, melanin, cutin, cutan, latex, rubber, and mixtures thereof.

12. The method of claim 9, wherein the polysaccharide is selected from the group consisting of: cellulose, nanocellulose, nanofibrillated cellulose, hemicellulose, xylan, lignin, lignosulfonate, chitin, pectin, arabinoxylan, starch, glycogen, inulin, xanthan gum, guar gum, agar, agarose, alginate, chitosan, heparin, and mixtures thereof; preferably he polysaccharide is cellulose, nanocellulose, nanofibrillated cellulose, hemicellulose, and / or pectin.

13. The method of any one of claims 1-12, wherein the synthetic polymer is selected from the group consisting of: polyamide, polyimide, polyacrylamide, polyacrylate, polyacrylonitrile, polycyanurate, polyurea, polyurethane, polyisocyanurate, polyaramid, polyester, polyamine, polycarbonate, polyether, polyol, polyvinyl alcohol, polyvinyl alcohol dialdehyde, polyvinyl ester, polyaldehyde, phenolic resin, resorcinol formaldehyde (polymer / resin), phenol formaldehyde (polymer / resin), melamine formaldehyde (polymer / resin), cresol formaldehyde (polymer / resin), phenol furfuryl alcohol, polyepoxide (epoxy), and mixtures thereof.

14. The method of any one of claims 1-13, wherein the organic compound is homogeneously distributed in the silica or organosilica gel, optionally wherein the organic compound is introduced into the silica or organosilica gel at the solution or sol state.

15. The method of any one of claims 1-14, wherein the weight percentage of the organic compound in the silica or organosilica gel is 0.001-20 wt%, preferably 0.01-10 wt%, more preferably 0.05-5 wt%, such as wherein the organic compound is introduced into the silicaor organosilica gel at the solution or sol state at 0.001-20 wt%, preferably 0.01-10 wt%, more preferably 0.05-5 wt% of the solution or sol.

16. The method of any one of claims 2-15, wherein the pore liquid comprises liquid CO2, alcohol, alkane, or ether solvent, preferably an alkyl alcohol, an alkane, or alkyl ether solvent, more preferably a Ci-isalkyl alcohol, a Ci-isalkane, or Ci-isalkyl ether solvent.

17. The method of any one of claims 1-16, wherein the at least partial pyrolysis of the organic compound forms a carbonaceous structure, and preferably wherein the carbonaceous structure provides hydrophobicity and opacification of the hybrid organic-inorganic silica aerogel or xerogel.

18. A hybrid organic-inorganic silica aerogel or xerogel, obtainable or obtained by the method of any one of claims 1 to 17, having- a specific capacitance of 20-100 F g’1, preferably 50-200 F g’1, preferably 100-300 F g'1; and / or- a mass extinction coefficient in the wavelength range of 2.3-10 pm of 10-50 m2kg'1, preferably 30-100 m2kg'1, preferably higher than 100 m2kg'1; optionally, a surface contact angle of greater than 100°; optionally, a thermal conductivity of less than 25 mW / m.K at 25°C; optionally, a 24-h water uptake of less than 15%.

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