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US-20260125611-A1 - MODIFIED REPEAT UNIT FOR ENHANCED INTERACTION ENERGY AND THERMAL STABILITY OF HIGH TEMPERATURE LUBRICANTS FOR MAGNETIC MEDIA

US20260125611A1US 20260125611 A1US20260125611 A1US 20260125611A1US-20260125611-A1

Abstract

High temperature lubricants for magnetic recording media are provided. One such lubricant has a plurality of segments according to general formula (I): where R n when present is a C 1 -C 4 repeating unit having a dipole moment greater than 0.036 D, R m when present is a C 1 -C 4 repeating unit having a dipole moment greater than 0.036 D and enthalpy of vaporization between 17 kJ/mol and 40.7 kJ/mol but different than R n , and at least one of R n or R n is present, R e is a first anchoring functional group, R v is optionally a second anchoring functional group and R d is a linker.

Inventors

  • Daniel Demori Maksuta
  • Hantao Zhou
  • Ao Fan
  • Jianming Wen
  • Charles Cheng-Hsing Lee

Assignees

  • WESTERN DIGITAL TECHNOLOGIES, INC.

Dates

Publication Date
20260507
Application Date
20241107

Claims (20)

  1. 1 . A lubricant comprising: a plurality of segments according to general formula (I): where: R n when present is a C 1 -C 4 fluorinated repeating unit having a dipole moment greater than 0.036 debye (D), R m when present is a C 1 -C 4 fluorinated repeating unit having a dipole moment greater than 0.036 D but different than R n , and at least one of R n or R m is present, R e is a first anchoring functional group, R v is optionally a second anchoring functional group, and R d is a linker.
  2. 2 . The lubricant of claim 1 , wherein the dipole moment of R n and R m are each independently in a range of 0.036 D to 1.69 D.
  3. 3 . The lubricant of claim 1 , wherein R n or R m , when present, have an enthalpy of vaporization of greater than 17 kiloJoules per mole (kJ/mole) and less than 40.7 kJ/mol.
  4. 4 . The lubricant of claim 1 , wherein R e has an enthalpy of vaporization of between 60 kJ/mol and 70 kJ/mol.
  5. 5 . The lubricant of claim 1 , wherein R n and R m are each independently selected from:
  6. 6 . The lubricant of claim 1 , wherein R n and R m are each independently formed from: benzyl phenyl ether, phenylmethyl ether, dimethyl ether, difluorodimethyl ether or perfluorodimethyl ether.
  7. 7 . The lubricant of claim 1 , wherein R n and R m each independently comprises moieties selected from hexafluoroacetone, heaxfluoroisopropanol, perfluoroethanamine, 3,3,3-Trifluoro-2-(trifluoromethyl)propanal or 1,1,1-Trifluoro-N-(trifluoromethyl)methanamine.
  8. 8 . The lubricant of claim 1 , wherein R e and R v independently each comprises at least one of B, Si, a pnictogen, a chalcogen, a halogen, —OR*, —NR* 2 , —NR*—CO—R*, —O—CO—R*, —CO—O—R*, —SeR*, —TeR*, —PR* 2 , —PO—(OR*) 2 , —O—PO—(OR*) 2 , —N═P(NR* 2 ) 3 , —AsR* 2 , —SR*, —SO 2 —(OR*) 2 , —BR* 2 , —SiR* 3 , —(CH 2 ) q —SiR* 3 , —(CF 2 ) q —SiR* 3 , or a combination thereof, wherein q is 1 to 10 and each R* is, independently, a hydrogen, B, Si, a pnictogen, a chalcogen, a halogen, a saturated C 1 -C 50 radical, an unsaturated C 2 -C 50 radical, an aromatic C 4 -C 50 radical, a polycyclic aromatic C 5 -C 50 radical, a heteroaromatic C 5 -C 50 radical, an alicyclic C 3 -C 50 radical, and/or a heterocyclic C 2 -C 50 radical, and wherein two or more R* may join together to form a ring structure.
  9. 9 . The lubricant of claim 1 , wherein R e and R v each comprises a hydroxyl (—OH) moiety.
  10. 10 . A data storage system, comprising: at least one magnetic head; a magnetic recording medium including the lubricant of claim 1 ; a drive mechanism for positioning the at least one magnetic head over the magnetic recording medium; and a controller electrically coupled to the at least one magnetic head for controlling operation of the at least one magnetic head.
  11. 11 . The data storage system of claim 10 , wherein the lubricant is a monolayer with a thickness being 5 to 12 Å on average.
  12. 12 . The data storage system of claim 10 , wherein the lubricant is a monolayer with a thickness being 8 Å on average.
  13. 13 . A magnetic recording medium, comprising: a magnetic recording layer on a substrate; a protective overcoat on the magnetic recording layer; and a lubricant layer comprising the lubricant according to claim 1 on the protective overcoat.
  14. 14 . A data storage system, comprising: a slider comprising at least one magnetic head and an air bearing surface (ABS), wherein the lubricant according to claim 1 is disposed on the ABS; and a magnetic recording medium including a magnetic recording layer; wherein the slider is configured to write information to the magnetic recording layer using heat assisted magnetic recording (HAMR).
  15. 15 . A method of synthesizing a component of the lubricant of claim 1 , comprising atom transfer radical polymerization (ATRP) followed by Simon's/Fowler's process to yield formula (IX):
  16. 16 . A method of synthesizing a component of the lubricant of claim 1 , comprising a ring opening based on cyclobutane polymerization using an acid or base to yield a lubricant of formula (X):
  17. 17 . A method of synthesizing a component of the lubricant of claim 1 , comprising perfluorination of a non-fluorinated polymer by Simon/Fowler's process to yield formula (XI):
  18. 18 . A lubricant comprising: a plurality of segments according to general formula (I): where: R n when present is a C 1 -C 4 fluorinated repeating unit having an enthalpy of vaporization of greater than 17 kiloJoules per mole (kJ/mole) and less than 40.7 kJ/mol, R m when present is a C 1 -C 4 fluorinated repeating unit having an enthalpy of vaporization of greater than 17 kJ/mole and less than 40.7 kJ/mol, but different than R n , and at least one of R n or R m is present, R e is a first anchoring functional group, R v is optionally a second anchoring functional group, and R d is a linker.
  19. 19 . The lubricant of claim 18 , wherein R e has an enthalpy of vaporization of between 60 and 70 kJ/mol.
  20. 20 . The lubricant of claim 18 , wherein a dipole moment of R n and R m are each independently in a range of 0.036 D to 1.69 D.

Description

FIELD The disclosure relates to lubricants, and more particularly, to high temperature lubricants, which may be used with media configured for magnetic recording, e.g., for Heat Assisted Magnetic Recording (HAMR) having modified repeat units with optimized dipole moments and enthalpies. INTRODUCTION Magnetic storage systems, such as a hard disk drive (HDD), are utilized in a wide variety of devices in both stationary and mobile computing environments. Examples of devices that incorporate magnetic storage systems include data center storage systems, desktop computers, portable notebook computers, portable hard disk drives, network storage systems, high definition television (HDTV) receivers, vehicle control systems, cellular or mobile telephones, television set top boxes, digital cameras, digital video cameras, video game consoles, and portable media players. A typical disk drive includes magnetic storage media in the form of one or more flat disks or platters. The disks generally include two main components, namely, a substrate material that gives it structure and rigidity, and a magnetic medium coating that stores the magnetic signals that represent data in a recording layer within the coating. The typical disk drive also includes a read head and a write head, generally in the form of a magnetic transducer which can sense and/or change the magnetic fields stored on the recording layer of the disks. HAMR is a recording technique that can increase the areal density capability (ADC) of written data on a magnetic storage medium having very high coercivity with high-temperature assistance. However, the high recording temperatures applied to the medium may present challenges. Other examples of magnetic storage media include flexible tape media usable for magnetic tape recording. As a result of the high temperatures associated with HAMR technology, suitable lubricants for use in HAMR media may benefit from high thermal stability. However, high temperatures may increase the presence of contaminants and cause thermally activated reactions such as decomposition and polymerization which will cause discoloring, i.e., fogging, of the storage medium. It is therefore desirable to find lubricant chemistries that will inhibit thermally activated reactions while maintaining high evaporation temperature. As such, there is a need in the art for high temperature lubricants having properties suitable for use in HAMR drives, including repeat units that enhance interaction energy and thermal stability. SUMMARY In one aspect, this disclosure, in part, provides a lubricant that may include a number of segments according to general formula (I): where Rn when present is a C1-C4 fluorinated repeating unit having a dipole moment greater than 0.036 debye (D), Rm when present is a C1-C4 fluorinated repeating unit having a dipole moment greater than 0.036 D but different than Rn, and at least one of Rn or Rm is present, Re is a first anchoring functional group, Rv is optionally a second anchoring functional group. In the disclosure, the dipole moment of Rn and Rm may be each independently in a range of 0.036 D to 1.69 D. Rn or Rm, when present, may have an enthalpy of vaporization of greater than 17 kiloJoules per mole (kJ/mole) and less than 40.7 kJ/mol. Re may have an enthalpy of vaporization of between 60 kJ/mol and 70 kJ/mol. In the disclosure, Rn and Rm may be each independently selected from: In the disclosure, Rn and Rm may each be independently formed from: benzyl phenyl ether, phenylmethyl ether, dimethyl ether, difluorodimethyl ether or perfluorodimethyl ether. Rn and Rm may each independently include moieties selected from hexafluoroacetone, heaxfluoroisopropanol, perfluoroethanamine, 3,3,3-Trifluoro-2-(trifluoromethyl)propanal or 1,1,1-Trifluoro-N-(trifluoromethyl)methanamine. Re and Rv may independently each include at least one of B, Si, a pnictogen, a chalcogen, a halogen, —OR*, —NR*2, —NR*—CO—R*, —O—CO—R*, —CO—O—R*, —SeR*, —TeR*, —PR*2, —PO—(OR*)2, —O—PO—(OR*)2, —N═P(NR*2)3, —AsR*2, —SR*, —SO2—(OR*)2, —BR*2, —SiR*3, —(CH2)q—SiR*3, —(CF2)q—SiR*3, or a combination thereof, wherein q is 1 to 10 and each R* is, independently, a hydrogen, B, Si, a pnictogen, a chalcogen, a halogen, a saturated C1-C50 radical, an unsaturated C2-C50 radical, an aromatic C4-C50 radical, a polycyclic aromatic C5-C50 radical, a heteroaromatic C5-C50 radical, an alicyclic C3-C50 radical, and/or a heterocyclic C2-C50 radical, and wherein two or more R* may join together to form a ring structure, or a hydroxyl (—OH) moiety. The disclosure, in part, pertains to a data storage system that may include at least one magnetic head; a magnetic recording medium including the lubricant of the disclosure; a drive mechanism for positioning the at least one magnetic head over the magnetic recording medium; and a controller electrically coupled to the at least one magnetic head for controlling operation of the at least one magnetic head. In the data storage system,