Patents by Inventor Daniel Ratchford

Daniel Ratchford has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Photochromic liquid crystal electrospun coaxial polymer fibers
    Patent number: 12595595
    Abstract: A fiber having a polymer sheath and a core. The core has a liquid crystal and a compound capable of photoisomerization, such as that shown below. A method of: providing a first solution of a polymer, providing a second solution of a liquid crystal and compound capable of photoisomerization, and electrospinning the first solution and the second solution to form the fiber.
    Type: Grant
    Filed: September 15, 2021
    Date of Patent: April 7, 2026
    Assignee: The Government of the United States of America, as represented by the Secretary of the Navy
    Inventors: Jeffrey G. Lundin, Matthew D. Thum, Riccardo Casalini, Daniel Ratchford
  • Color changing coaxial polymer fibers
    Patent number: 12590204
    Abstract: Disclosed herein is a fiber having a sheath including a polymer and a core including a non-cholesteric liquid crystal. The sheath is transparent to visible light. The fiber may an average diameter of no more than 10 microns, and at least 90% of the fiber has a diameter within 20% of the average diameter. The sheath may include a compound capable of photoisomerization that extends into the core. The interference color of the fiber may be reversibly changed by exposure to light or a temperature change.
    Type: Grant
    Filed: October 7, 2022
    Date of Patent: March 31, 2026
    Assignee: The Government of the United States of America, as represented by the Secretary of the Navy
    Inventors: Jeffrey G. Lundin, Matthew D. Thum, Jakub Kolacz, Daniel Ratchford
  • PHOTOLITHOGRAPHIC FABRICATION OF SILICON PILLAR ARRAYS WITH PERFORATED TOP ELECTRODE FOR TRACE VAPOR
    Publication number: 20260086074
    Abstract: Systems and methods are provided for improving the fabrication of silicon pillar arrays and porous top electrodes for trace vapor preconcentration and partial separation. In an embodiment, the silicon pillar arrays are fabricated using photolithography or maskless photolithography combined with a dry etching process. Importantly, this process is more reproducible and scalable than the past fabrication method and yields better device performance.
    Type: Application
    Filed: September 23, 2025
    Publication date: March 26, 2026
    Applicant: The Government of the United States of America, as represented by the Secretary of the Navy
    Inventors: Daniel Ratchford, Braden Giordano, Junghoon Yeom
  • COLOR CHANGING COAXIAL POLYMER FIBERS
    Publication number: 20230115308
    Abstract: Disclosed herein is a fiber having a sheath including a polymer and a core including a non-cholesteric liquid crystal. The sheath is transparent to visible light. The fiber may an average diameter of no more than 10 microns, and at least 90% of the fiber has a diameter within 20% of the average diameter. The sheath may include a compound capable of photoisomerization that extends into the core. The interference color of the fiber may be reversibly changed by exposure to light or a temperature change.
    Type: Application
    Filed: October 7, 2022
    Publication date: April 13, 2023
    Applicant: The Government of the United States of America, as represented by the Secretary of the Navy
    Inventors: Jeffrey G. Lundin, Matthew D. Thum, Jakub Kolacz, Daniel Ratchford
  • PHOTOCHROMIC LIQUID CRYSTAL ELECTROSPUN COAXIAL POLYMER FIBERS
    Publication number: 20220081804
    Abstract: A fiber having a polymer sheath and a core. The core has a liquid crystal and a compound capable of photoisomerization, such as that shown below. A method of: providing a first solution of a polymer, providing a second solution of a liquid crystal and compound capable of photoisomerization, and electrospinning the first solution and the second solution to form the fiber.
    Type: Application
    Filed: September 15, 2021
    Publication date: March 17, 2022
    Applicant: The Government of the United States of America, as represented by the Secretary of the Navy
    Inventors: Jeffrey G. Lundin, Matthew D. Thum, Riccardo Casalini, Daniel Ratchford
  • Nanowire arrays for trace vapor preconcentration
    Patent number: 11046579
    Abstract: Disclosed herein is a method of providing a structure having two electrodes connected by nanowires, exposing the structure to an analyte that can adsorb onto the nanowires, and passing an electrical current through the nanowires to heat the nanowires to desorb the analyte. Also disclosed herein is an apparatus having the above structure; a current source electrically connected to the electrodes, and a detector to detect the analyte.
    Type: Grant
    Filed: December 9, 2019
    Date of Patent: June 29, 2021
    Assignee: The Government of the United States of America, as represented by the Secretary of the Navy
    Inventors: Braden C. Giordano, Pehr E. Pehrsson, Kevin J. Johnson, Daniel Ratchford, Christopher Field, Junghoon Yeom
  • NANOWIRE ARRAYS FOR TRACE VAPOR PRECONCENTRATION
    Publication number: 20200109049
    Abstract: Disclosed herein is a method of providing a structure having two electrodes connected by nanowires, exposing the structure to an analyte that can adsorb onto the nanowires, and passing an electrical current through the nanowires to heat the nanowires to desorb the analyte. Also disclosed herein is an apparatus having the above structure; a current source electrically connected to the electrodes, and a detector to detect the analyte.
    Type: Application
    Filed: December 9, 2019
    Publication date: April 9, 2020
    Applicant: The Government of the United States of America, as represented by the Secretary of the Navy
    Inventors: Braden C. Giordano, Pehr E. Pehrsson, Kevin J. Johnson, Daniel Ratchford, Christopher Field, Junghoon Yeom
  • Nanowire arrays for trace vapor preconcentration
    Patent number: 10501316
    Abstract: Disclosed herein is a method of providing a structure having two electrodes connected by nanowires, exposing the structure to an analyte that can adsorb onto the nanowires, and passing an electrical current through the nanowires to heat the nanowires to desorb the analyte. Also disclosed herein is an apparatus having the above structure; a current source electrically connected to the electrodes, and a detector to detect the analyte.
    Type: Grant
    Filed: April 18, 2018
    Date of Patent: December 10, 2019
    Assignee: The Government of the United States of America, as represented by the Secretary of the Navy
    Inventors: Braden C. Giordano, Pehr E. Pehrsson, Kevin J. Johnson, Daniel Ratchford, Christopher Field, Junghoon Yeom
  • NANOWIRE ARRAYS FOR TRACE VAPOR PRECONCENTRATION
    Publication number: 20180237294
    Abstract: Disclosed herein is a method of providing a structure having two electrodes connected by nanowires, exposing the structure to an analyte that can adsorb onto the nanowires, and passing an electrical current through the nanowires to heat the nanowires to desorb the analyte. Also disclosed herein is an apparatus having the above structure; a current source electrically connected to the electrodes, and a detector to detect the analyte.
    Type: Application
    Filed: April 18, 2018
    Publication date: August 23, 2018
    Applicant: The Government of the United States of America, as represented by the Secretary of the Navy
    Inventors: Braden C. Giordano, Pehr E. Pehrsson, Kevin J. Johnson, Daniel Ratchford, Christopher Field, Junghoon Yeom