Water-responsive materials and uses therefor

{
  "publication_number": "US12264207B2",
  "country": "US",
  "kind": "B2",
  "title": "Water-responsive materials and uses therefor",
  "abstract": "A rotary engine that generates electricity using differences in relative humidity. A water-responsive material expands and contracts as water evaporates which drives the rotation of two wheels. The rotary motion drives an electrical generator which produces electricity. In another embodiment, the water-responsive material is used to actuate an artificial muscle of a robotic device.",
  "claims": [
    "1. A method for actuating an artificial muscle, the method comprising: exposing a flexible substrate to air with a first humidity, wherein the flexible substrate comprises a surface that is coated with a peptidoglycan from a bacterial cell wall; and exposing the substrate to air with a second humidity, different than the first humidity, wherein the second humidity causes a change in hygroscopic expansion or contraction of the peptidoglycan, thereby actuating the substrate.",
    "2. The method as recited in claim 1, wherein the peptidoglycan is peptidoglycan from the bacterial cell wall of Bacillus subtilis.",
    "3. The method as recited in claim 1, wherein peptidoglycan is mixed with a secondary component selected from a group consisting of an epoxy, a cellulose, a collagen and a polymer adhesive.",
    "4. The method as recited in claim 1, wherein the peptidoglycan is cross-linked by a crosslinker.",
    "5. The method as recited in claim 1, wherein the hygroscopic expansion and contraction of the peptidoglycan is transferred to a secondary movement selected from rotational movement, expansion, contraction or a combination thereof.",
    "6. The method as recited in claim 1, wherein the flexible substrate has a thickness between 500 nm and 5 mm.",
    "7. The method as recited in claim 1, wherein the flexible substrate has a Yong's modulus between 10 kPa and 10 GPa.",
    "8. A method for actuating an artificial muscle, the method comprising: exposing a flexible substrate to air with a first humidity, wherein the flexible substrate comprises a surface that is coated with a peptidoglycan; exposing the substrate to air with a second humidity, different than the first humidity, wherein the second humidity causes a change in hygroscopic expansion or contraction of the peptidoglycan, thereby actuating the substrate; and wherein the peptidoglycan is cross-linked by an amphiphilic peptide stem.",
    "9. A method for actuating an artificial muscle, the method comprising: exposing a flexible substrate to air with a first humidity, wherein the flexible substrate comprises a surface that is coated with a peptidoglycan; exposing the substrate to air with a second humidity, different than the first humidity, wherein the second humidity causes a change in hygroscopic expansion or contraction of the peptidoglycan, thereby actuating the substrate; and wherein the peptidoglycan is cross-linked by a crosslinker selected from a group consisting of glutaraldehyde, O,O′-Bis[2-(N-Succinimidyl-succinylamino)ethyl]polyethylene glycol, and BS(PEG)9 (PEGylated bis(sulfosuccinimidyl)suberate).",
    "10. An artificial muscle comprising: a flexible substrate with a surface that is coated with a peptidoglycan from a bacterial cell wall, the peptidoglycan having with a thickness between 500 nm and 5 mm, wherein humid air contacting the peptidoglycan causes hygroscopic expansion and contraction of the peptidoglycan, thereby actuating the substrate.",
    "11. The artificial muscle according to claim 10, wherein the peptidoglycan is peptidoglycan from the bacterial cell wall of Bacillus subtilis.",
    "12. The artificial muscle according to claim 10, wherein peptidoglycan is mixed with a secondary component selected from a group consisting of an epoxy, a cellulose, a collagen and a polymer adhesive.",
    "13. The artificial muscle according to claim 10, wherein the peptidoglycan is cross-linked by a crosslinker.",
    "14. The artificial muscle according to claim 10, wherein the hygroscopic expansion and contraction of the peptidoglycan in the artificial muscle relies on the changes in local relative humidity level or temperature.",
    "15. The artificial muscle according to claim 10, wherein the hygroscopic expansion and contraction of the peptidoglycan is transferred to a secondary movement selected from rotational movement, translational movement, expansion, contraction or a combination thereof.",
    "16. An artificial muscle comprising: a flexible substrate with a surface that is coated with a peptidoglycan with a thickness between 500 nm and 5 mm, wherein humid air contacting the peptidoglycan causes hygroscopic expansion and contraction of the peptidoglycan, thereby actuating the substrate; and wherein the peptidoglycan is cross-linked by an amphiphilic peptide stem.",
    "17. An artificial muscle comprising: a flexible substrate with a surface that is coated with a peptidoglycan with a thickness between 500 nm and 5 mm, wherein humid air contacting the peptidoglycan causes hygroscopic expansion and contraction of the peptidoglycan, thereby actuating the substrate; and wherein the peptidoglycan is cross-linked by a crosslinker selected from a group consisting of glutaraldehyde, O,O′-Bis[2-(N-Succinimidyl-succinylamino)ethyl]polyethylene glycol, and BS(PEG)9 (PEGylated bis(sulfosuccinimidyl)suberate)."
  ],
  "description_excerpt": "The subject matter disclosed herein relates to the production of energy using renewal green sources. In another embodiment, the subject matter relates the actuation of a robotic appendage using an artificial muscle.\n\nThe human need for sources of electrical energy is consistently increasing. At the same time, concerns related to fossil fuels and climate change have rendered many forms of electrical energy production less desirable. The green-energy industry has responded by developing additional methods of generating electricity that are more environmentally friendly.\n\nOne critical drawback of sources of green energy is the factor of environmental dependency. Hydroelectric power-plants need natural or human-constructed falls and dams. Photovoltaic cells need ample exposure to sunlight and windmills require strong winds. It would be desirable to provide additional methods for generating green energy and thereby expand the number of available options.\n\nThe discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.\n\nA rotary engine that generates electricity using differences in relative humidity (a relative humidity gradient). A water-responsive material expands and contracts as water evaporates which drives the rotation of wheels. The rotary motion drives an electrical generator which produces electricity. In another embodiment, the water-responsive material is used to actuate an artificial muscle of a robotic device.",
  "cpc": [
    "C08B 37/0081",
    "B25J 9/0015",
    "B25J 9/1075",
    "B25J 9/1095",
    "C08B 37/006",
    "C08B 37/0063",
    "C08L 1/02",
    "C08L 89/00",
    "C09D 105/00",
    "C09J 105/00",
    "F03G 7/06",
    "F03G 7/061"
  ],
  "ipc": [
    "B25J 9/00",
    "B25J 9/10",
    "C08B 37/00",
    "C09D 105/00",
    "F03G 7/06"
  ],
  "assignees": [
    "Research Foundation of City University of New York"
  ],
  "inventors": [
    "Xi Chen",
    "Rein V. Ulijn",
    "Zhi-Lun Liu",
    "Yi-Ren WANG",
    "Daniela Kroiss",
    "Haozhen Wang"
  ],
  "filing_date": "2021-03-26",
  "publication_date": "2025-04-01",
  "grant_date": "2025-04-01",
  "priority_date": "2018-04-06",
  "application_number": "US-202117214132-A",
  "family_id": "76760867",
  "cited_by_count": 3,
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}