Triboelectric generator with embossed honeycomb pattern

A triboelectric generator comprising:

• a first contact charging member comprising a contact layer with a contact side and a back side, made of a dielectric material that has a triboelectric series rating indicating a propensity to exchange electrons due to a contacting event, and an electrode layer disposed along the back side of the contact layer;
• a second contact charging member comprising a contact layer with a contact side and a back side, made of a dielectric material that has a triboelectric series rating indicating a propensity to exchange electrons due to a contacting event, and an electrode layer disposed along the back side of the contact layer;
• wherein the first and second contact charging members have their contact sides in front of each other and are configured to allow at least one of a pressing and sliding contact between the contact sides;
• wherein the contact side of the first contact layer is patterned so as to show a series of cavities, each with an opening wand a bottom that is flexible such as to elastically deform up to the opening, and
• wherein the cavities of the contact layer of the first contact charging member show an average radius a that is such that a mechanical force Fmeca of the bottom when deformed up to the opening is at least 5 times larger than an electrostatic force Felec between the contact layer and the contact layer of the second contact charging member.

A process for manufacturing a contact charging member comprising a contact layer with a contact side and a back side, made of a dielectric material that has a triboelectric series rating indicating a propensity to exchange electrons due to a contacting event, comprising the step of:

• patterning the contact side of the contact layer;
• wherein the patterning step comprises embossing the contact layer so as to form a series of circular or hexagonal cavities with a flat bottom;
• the process comprising a further step of
• applying an electrode layer on the back side of the contact layer, the contact charging member comprising:
• the contact layer with the contact side and the back side, made of a dielectric material that has a triboelectric series rating indicating a propensity to exchange electrons due to a contacting event;
• and
• an electrode layer disposed along the back side of the contact layer;
• and
• wherein the contact side of the contact layer is patterned so as to show a series of cavities, each with an opening and a bottom that is flexible such as to elastically deform up to the opening, and
• wherein the dielectric material of the first contact charging member is fluorinated ethylene propylene FEP, the contact side of the member showing a super hydrophobic behaviour, and the dielectric material of the second contact charging member is polyimide PI, the contact side of the member showing a super hydrophilic behaviour.

A process for manufacturing moulds for manufacturing by embossing a contact charging member comprising a contact layer with a contact side and a back side, made of a dielectric material that has a triboelectric series rating indicating a propensity to exchange electrons due to a contacting event, wherein the contact side of the contact layer is patterned so as to show a series of cavities, each with an opening and a bottom that is flexible such as to elastically deform up to the opening, comprising the following steps:

• providing a first metal plate and a second metal plate;
• coating a main face of the first metal plate with a negative photoresist mask of the pattern and coating a main face of the second metal plate with a positive photoresist mask of the pattern;
• applying photolithography to the main faces of the first and second metal plates, provided with the masks;
• removing the masks on the first and second metal plates;
• and
• structuring a relief of the moulds by wet chemical etching in depth of the metal plates on the areas previously not covered by the photoresist masks,
• wherein the dielectric material of the first contact charging member is fluorinated ethylene propylene FEP, the contact side of the member showing a super hydrophobic behaviour, and the dielectric material of the second contact charging member is polyimide PI, the contact side of the member showing a super hydrophilic behaviour.

A contact charging member for a triboelectric generator, comprising:

• a contact layer with a contact side and a back side, made of a dielectric material that has a triboelectric series rating indicating a propensity to exchange electrons due to a contacting event;
• and
• an electrode layer disposed along the back side of the contact layer;
• wherein the contact side of the contact layer is patterned so as to show a series of cavities, each with an opening and a bottom that is flexible such as to elastically deform up to the opening, and
• wherein the back side is patterned in negative and in correspondence with the contact side.