Lubricants and methods to determine dewetting thickness thereof
AssigneeWestern Digital Technologies, Inc.
InventorsBala Krishna Pathem, Nicholas Ryan Conley, Bruno Jean Marchon
Life of this patent
Estimating the term…
Abstract
A lubricant including a plurality of segments including a divalent center segment and two sidechain segments, each including a perfluoroalkyl ether moieties is provided in which a dewetting thickness of the lubricant may be determined based in-part on a segment weight average molecular weight of the segments. A magnetic recording medium and a magnetic data storage system including the lubricant are also provided.
Claims25
A lubricant comprising:
- a plurality of segments, each linked together by ether linkages according to a general formula:
- Re1-Rb1-Ri-Rc-Ri-Rb2-Re2;
- wherein Rc is a divalent center segment including a perfluoroalkyl ether moiety;
- wherein each of Rb1 and Rb2 is, independently, a sidechain segment including a perfluoroalkyl ether moiety;
- wherein each Ri is, independently, a divalent linking segment including a functional group including elements from Group 13-17 of the periodic table of the elements;
- wherein each of Re1 and Re2 is, independently, a monovalent end segment including a functional group including elements from Group 13-17 of the periodic table of the elements;
- wherein Rb1≠Rc≠Rb2;
- and
- wherein the lubricant comprises:
- a segment weight average molecular weight (a) determined according to the formula:
- α=[molecular weight of Rb1+molecular weight of Rb2+molecular weight of Rc]÷3;
- and
- wherein a dewetting thickness of the lubricant Tdw is determined according to the formula:
- Tdw=ψ(α);
- wherein ψ is a function determined from a relationship between a dewetting thickness and a segment weight average molecular weight of a plurality of other lubricants;
- wherein each of the plurality of other lubricants includes one or more segments including perfluoroalkyl ether moieties;
- wherein the segment weight average molecular weight of each of the other lubricants is equal to a weight average molecular weight of the one or more segments including perfluoroalkyl ether moieties present in the respective other lubricant;
- and
- wherein the segment weight average molecular weight of each of the plurality of other lubricants is from about 300 g/mol to about 5,000 g/mol.
A lubricant comprising a plurality of segments linked together by ether linkages according to a formula:
- wherein each of x, y1, and y2 is an integer from 1 to 10;
- wherein y1≠x≠y2;
- and
- comprising a dewetting thickness Tdw=0.0045(α)+8.0226;
- wherein α=(116.015*y1+116.015*y2+116.015*x)÷3.
A method to determine a dewetting thickness of a lubricant, comprising:
- a) generating a chemical representation of the lubricant including a plurality of segments, each linked together through an ether linkage according to a general formula:
- Re1-Rb1-Ri-Rc-Ri-Rb2-Re2;
- wherein Rc is a divalent center segment including a perfluoroalkyl ether moiety;
- wherein each of Rb1 and Rb2 is, independently, a sidechain segment including a perfluoroalkyl ether moiety;
- wherein each Ri is, independently, a divalent linking segment including a functional group including elements from Group 13-17 of the periodic table of the elements;
- wherein each of Re1 and Re2 is, independently, a monovalent end segment including a functional group including elements from Group 13-17 of the periodic table of the elements;
- and
- wherein Rb1≠Rc≠Rb2;
- b) determining a segment weight average molecular weight (a) according to the formula:
- α=[molecular weight of Rb1+molecular weight of Rb2+molecular weight of Rc]÷3;
- and
- c) determining the dewetting thickness Tdw of the lubricant according to the formula:
- Tdw=0.0045(α)+8.0226.
Dependencies are inferred from the claim text.