Abstract: There is a process for preparing in situ an aqueous gel ink with fixed color having the following steps: (i) preparing a gel-based matrix of aqueous ink comprising 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid as reducing agent, and (ii) adding a solution of metallic salts to the gel-based matrix of aqueous ink prepared in step (i), to obtain an aqueous gel ink with fixed color with metallic nanoparticles dispersed therein. There is also an aqueous gel ink with fixed color obtained according to the process of the disclosure, comprising 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid and metallic nanoparticles. There is also a writing instrument comprising an aqueous gel ink with fixed color according to the disclosure.

Abstract: The present invention concerns a process for preparing in situ an aqueous gel ink with variable color comprising the following steps: (i) preparing a gel-based matrix of aqueous ink comprising 0.005 to 0.1 mol·L?1 of ester(s) of retinol represented by formula (I), and (ii) adding a solution of 0.002 to 0.05 mol·L?1 silver salts (Ag+) to the gel-based matrix of aqueous ink prepared in step (i), to obtain an aqueous gel ink with variable color with silver nanoparticles dispersed therein. The present invention also relates to an aqueous gel ink with variable color obtained according to the process of the invention, comprising said ester of retinol represented by formula (I) and silver nanoparticles. The invention finally concerns a writing instrument comprising an aqueous gel ink with variable color according to the invention.

Abstract: A kit comprising a) an aqueous writing ink composition, containing—metal nanoparticles as coloring agent wherein the metal nanoparticles essentially consists of metal and the metal is chosen from silver, gold, aluminum and/or copper and—a dispersing agent, and b) an eradicator fluid containing at least one oxidizing agent. An aqueous eradicator fluid for erasing an aqueous writing ink composition containing metal nanoparticles as the coloring agent, in which the fluid contains an oxidizing agent and—a volatile solvent. A writing instrument containing the eradicator fluid, the use of the eradicator fluid and/or of the kit containing it and a method of correcting errors of a written mark made on a porous substrate.

Abstract: The present invention concerns a kit comprising a) an aqueous writing ink composition, containing—metal nanoparticles as coloring agent wherein said metal nanoparticles essentially consists of metal and said metal is chosen from silver, gold, aluminum and/or copper and—a dispersing agent, and b) an eradicator fluid containing at least one oxidizing agent. It also concerns an aqueous eradicator fluid for erasing an aqueous writing ink composition containing metal nanoparticles as the coloring agent, in which said metal nanoparticles said fluid containing—an oxidizing agent and—a volatile solvent. It further concerns a writing instrument containing the eradicator fluid, the use of the eradicator fluid and/or of the kit containing it and a method of correcting errors of a written mark made on porous substrate.

Abstract: A process for preparing in situ an aqueous gel ink with fixed color comprising the following steps: (i) preparing a gel-based matrix of aqueous ink comprising ester(s) of retinol represented by formula (I), and (ii) adding a solution of gold salts (Au3+) to the gel-based matrix of aqueous ink prepared in step (i), to obtain an aqueous gel ink with fixed color with gold nanoparticles dispersed therein. An aqueous gel ink with fixed color obtained according to the process of the invention, comprising the ester of retinol represented by formula (I) and gold nanoparticles. A writing instrument comprising an aqueous gel ink with fixed color.

Abstract: There is a process for preparing in situ an aqueous gel ink with variable color having the following steps: (i) preparing a gel-based matrix of aqueous ink comprising a reducing agent, (ii) adding a solution of metallic salts, (iii) adding iron powder to obtain an aqueous gel ink with variable color, wherein the steps (ii) and (iii) can be interchanged. There also is an aqueous gel ink with variable color obtained according to the process of the disclosure, having a reducing agent, metallic nanoparticles and iron powder. There further is a writing instrument having an aqueous gel ink with variable color according to the disclosure.

Abstract: A process for preparing in situ an aqueous gel ink with variable color comprising the following steps: (i) preparing a gel-based matrix of aqueous ink comprising an N-Acyl-aminophenol, wherein the hydroxyl group is preferably in meta or para position on the benzenic group, and (ii) adding a solution of silver salts to the gel-based matrix of aqueous ink prepared in step (i), to obtain an aqueous gel ink with variable color with silver nanoparticles disposed therein. An aqueous gel ink with variable color obtained according to process for preparing, comprising an N-Acyl-aminophenol, wherein the hydroxyl group is preferably in meta or para position on the benzenic group and silver nanoparticles. A writing instrument comprising an aqueous gel ink with variable color.

Abstract: The invention relates a process for preparing an aqueous gel ink with fixed color comprising the following steps: (i) preparing a gel-based matrix of aqueous ink; (ii) preparing an aqueous suspension of gold or silver nanoparticles with a fixed color; (iii) adding the aqueous suspension of gold or silver nanoparticles obtained in step (ii) to the gel-based matrix of aqueous ink obtained in step (i).

Abstract: The present invention concerns a process for preparing an aqueous gel ink with fixed color comprising the following steps: (i) preparing a gel-based matrix of aqueous ink; (ii) preparing an aqueous suspension of silver nanoparticles with a fixed color by mixing silver salts with: —water, —a mixture of at least an alkali metal or alkaline earth metal salt of citrate, —an oxidizing agent, preferably hydrogen peroxide H2O2, —and polyvinylpyrrolidone; (iii) adding under agitation the aqueous suspension of silver nanoparticles obtained in step (ii) to the gel-based matrix of aqueous ink obtained in step (i), to obtain an aqueous gel ink with fixed color with silver nanoparticles dispersed therein.

Abstract: The present invention concerns a process for preparing in situ an aqueous gel ink with fixed color comprising the following steps: (i) preparing a gel-based matrix of aqueous ink comprising ester(s) of retinol represented by formula (I), and (ii) adding a solution of gold salts (Au3+) to the gel-based matrix of aqueous ink prepared in step (i), to obtain an aqueous gel ink with fixed color with gold nanoparticles dispersed therein. The present invention also relates to an aqueous gel ink with fixed color obtained according to the process of the invention, comprising said ester of retinol represented by formula (I) and gold nanoparticles. The invention finally concerns a writing instrument comprising an aqueous gel ink with fixed color according to the invention.

Abstract: The present invention concerns a process for preparing in situ an aqueous gel ink with fixed color comprising the following steps: (i) preparing a gel-based matrix of aqueous ink comprising reducing agent chosen in the group consisting of citric acid and/or derivatives of citric acid, (ii) adding a solution of gold salts, (iii) adding iron powder, (iv) adding polyvinylpyrrolidone to obtain an aqueous gel ink with fixed color, wherein the steps (ii) and (iii) can be interchanged. The present invention also relates to an aqueous gel ink with fixed color obtained according to the process of the invention, comprising citric acid and derivatives, gold nanoparticles, and iron powder. The invention finally concerns a writing instrument comprising an aqueous gel ink with fixed color according to the invention.

Abstract: The present invention concerns a process for preparing an aqueous gel ink with fixed color comprising the following steps: (i) preparing a gel-based matrix of aqueous ink; (ii) preparing an aqueous suspension of silver nanoparticles with fixed color by mixing silver salts with: water, a mixture of at least an alkali metal or alkaline earth metal salt of citrate, preferably an alkali citrate salt and an alkali metal hydride, preferably NaBH4, a further reducing agent, preferably ascorbic acid, and oxidizing agent, preferably hydrogen peroxide H2O2 (iii) adding under agitation the aqueous suspension of silver nanoparticles obtained in step (ii) to the gel-based matrix of aqueous ink obtained in step (i), to obtain an aqueous gel ink with fixed color with silver nanoparticles dispersed therein

Abstract: The present invention concerns a process for preparing in situ an aqueous gel ink with variable color comprising the following steps: (i) preparing a gel-based matrix of aqueous ink comprising an N-Acyl-aminophenol, wherein said hydroxyl group is preferably in meta or in para position on the benzenic group, and (ii) adding a solution of silver salts to the gel-based matrix of aqueous ink prepared in step (i), to obtain an aqueous gel ink with variable color with silver nanoparticles dispersed therein. The present invention also relates to an aqueous gel ink with variable color obtained according to the process of the invention, comprising an N-Acyl-aminophenol, wherein said hydroxyl group is preferably in meta or in para position on the benzenic group and silver nanoparticles. The invention finally concerns a writing instrument comprising an aqueous gel ink with variable color according to the invention.

Abstract: The present invention concerns a process for preparing in situ an aqueous gel ink with variable color comprising the following steps: (i) preparing a gel-based matrix of aqueous ink comprising 0.005 to 0.1 mol·L?1 of ester(s) of retinol represented by formula (I), and (ii) adding a solution of 0.002 to 0.05 mol·L?1 silver salts (Ag+) to the gel-based matrix of aqueous ink prepared in step (i), to obtain an aqueous gel ink with variable color with silver nanoparticles dispersed therein. The present invention also relates to an aqueous gel ink with variable color obtained according to the process of the invention, comprising said ester of retinol represented by formula (I) and silver nanoparticles.

Abstract: There is a process for preparing in situ an aqueous gel ink with variable color having the following steps: (i) preparing a gel-based matrix of aqueous ink comprising a reducing agent, (ii) adding a solution of metallic salts, (iii) adding iron powder to obtain an aqueous gel ink with variable color, wherein the steps (ii) and (iii) can be interchanged. There also is an aqueous gel ink with variable color obtained according to the process of the disclosure, having a reducing agent, metallic nanoparticles and iron powder. There further is a writing instrument having an aqueous gel ink with variable color according to the disclosure.

Abstract: There is a process for preparing in situ an aqueous gel ink with fixed color having the following steps: (i) preparing a gel-based matrix of aqueous ink comprising 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid as reducing agent, and (ii) adding a solution of metallic salts to the gel-based matrix of aqueous ink prepared in step (i), to obtain an aqueous gel ink with fixed color with metallic nanoparticles dispersed therein. There is also an aqueous gel ink with fixed color obtained according to the process of the disclosure, comprising 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid and metallic nanoparticles. There is also a writing instrument comprising an aqueous gel ink with fixed color according to the disclosure.

Abstract: Processes for obtaining a semiconductor nanodevice comprising a substrate, onto which patterned metal-oxide thin films having semiconductor properties are deposited, are provided, as well as semiconductor devices comprising them. The present invention belongs to the field of semiconductor nanodevices.