HIGH TEMPERATURE LUBRICANTS FOR MAGNETIC MEDIA HAVING MORE THERMALLY STABLE END GROUPS

1 . A lubricant comprising: a plurality of segments according to general formula (I), (II), or (III):

Re 1 —Rb 1 -Rc-Rb 2 —Re 2   (I);

Re 1 —Rb 1 —Re 2   (II); or

Re 1 —Rb 1 —(Rc-Rb 2 ) m -Re 2   (III);

wherein Rc is a divalent linking segment that optionally includes a first anchoring functional group engageable with a protective overcoat of a magnetic recording medium;

wherein each Rb 1 and Rb 2 independently comprises a chain segment comprising at least one of a fluoroalkyl ether moiety, a fluoroalkenyl ether moiety, a perfluoroalkyl ether moiety, a perfluoroalkenyl ether moiety, or a combination thereof;

wherein each of Re 1 and Re 2 independently comprises a group having a higher rotational energy barrier than that of CH 2 , terminating with at least one second anchoring functional group engageable with the protective overcoat of the magnetic recording medium comprising —CH 2 OCH 2 (CH 2 ) n (Ra) n-1 or —OCH 2 (CH 2 ) n (Ra) n-1 , wherein Ra is the second anchoring functional group, m=2 and n=2-10.

2 . The lubricant of claim 1 , wherein the first and second anchoring functional groups 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.

3 . The lubricant of claim 1 , wherein the first and second anchoring functional groups each comprises a hydroxyl (—OH) moiety.

4 . The lubricant of claim 1 , wherein Re 1 and Re 2 independently comprises —OCF 2 (CF 2 ) m —O—CH 2 ArRt, wherein Rt is —CH 2 OCH 2 (CH 2 ) n (Ra) n-1 or Rt is —OCH 2 (CH 2 ) n (Ra) n-1 , Ar is an aromatic group and Ra is the second anchoring functional group.

5 . The lubricant of claim 1 , wherein the group having a higher rotational energy barrier than that of CH 2 is an aromatic group.

6 . The lubricant of claim 1 , wherein the group having a higher rotational energy barrier than that of CH 2 is benzene or anisole.

7 . The lubricant of claim 1 , wherein the first and second anchoring functional groups independently comprises one or more of B, Si, a pnictogen, a chalcogen, a halogen, —OH, —NH 2 , —NH—CO—H, —O—CO—H, —CO—O—H, —SeH, —TeH, —PH 2 , —PO—(OH) 2 , —O—PO—(OH) 2 , —N=P(NH 2 ) 3 , —AsH 2 , —SH, —SO 2 —(OH) 2 , —BH 2 , —SiH 3 , —(CH 2 ) q —SiH 3 , —(CF 2 ) q —SiH 3 , or a combination thereof, wherein q is 1 to 10.

8 . The lubricant of claim 1 , wherein each Ra is independently selected from the group consisting of:

9 . The lubricant of claim 1 , wherein each Ra is independently selected from the group consisting of:

wherein n is 0 to 10 and m is 1 to 10.

10 . A lubricant, which comprises the general formula (XVII):

where n=1-10, the lubricant containing groups having a higher rotational energy barrier than that of CH 2 .

11 . The lubricant of claim 1 , which comprises the general formula (XVIII):

where n=1-10.

12 . The lubricant of claim 1 , wherein Rc comprises general formula (IXX):

wherein each Y independently comprises:

(i) —CH 2 —;

(ii) —CF 2 —;

(iii) —CHF—;

(iv) —CF 2 CF 2 CF 2 O(CF 2 CF 2 CF 2 CF 2 O) a CF 2 CF 2 CF 2 —;

(v) —CF 2 CF 2 O(CF 2 CF 2 CF 2 O) a CF 2 CF 2 —;

(vi) —CF 2 CF 2 O[CF(CF 3 )CF 2 O] a CF 2 CF 2 —;

(vii) —CF 2 O(CF 2 CF 2 O) a (CF 2 O) b CF 2 —;

(viii) —CF 2 O(CF 2 CF 2 O) a CF 2 —;

or a combination thereof;

wherein each a is independently from 1 to 20,

wherein each b is independently from 1 to 20;

wherein p is from 1 to 20; and

wherein at least one R 1 is an anchoring functional group engageable with a protective overcoat of a magnetic recording medium, comprising 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.

13 . The lubricant of claim 1 , wherein Rc, when present, comprises general formula (XX):

wherein each Q independently comprises:

(i) —CH 2 —;

(ii) —CF 2 —;

(iii) —CHF—;

(iv) —CF 2 CF 2 CF 2 O(CF 2 CF 2 CF 2 CF 2 O) a CF 2 CF 2 CF 2 —;

(v) —CF 2 CF 2 O(CF 2 CF 2 CF 2 O) a CF 2 CF 2 —;

(vi) —CF 2 CF 2 O[CF(CF 3 )CF 2 O] a CF 2 CF 2 —;

(vii) —CF 2 O(CF 2 CF 2 O) a (CF 2 O) b CF 2 —;

(viii) —CF 2 O(CF 2 CF 2 O) a CF 2 —;

or a combination thereof;

wherein each a, when present, is independently from 1 to 20,

wherein each b, when present, is independently from 1 to 20;

wherein n is from 1 to 20; and

wherein at least one R 1 is an anchoring functional group engageable with a protective overcoat of a magnetic recording medium, comprising 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, wherein two or more R* may join together to form a ring structure.

14 . The lubricant of claim 13 , wherein at least one R 1 comprises a hydroxyl moiety (—OH).

15 . The lubricant of claim 1 , wherein Rc, when present, comprises an ester functional group comprising general formula (XXI), (XXII), or a combination thereof:

wherein t, when present, is from 1 to 20; and

wherein s, when present, is from 1 to 20.

16 . The lubricant of claim 1 , wherein Rb 1 , and Rb 2 comprise the formula:

(iv) —CF 2 CF 2 CF 2 O(CF 2 CF 2 CF 2 CF 2 O) a CF 2 CF 2 CF 2 —;

(v) —CF 2 CF 2 O(CF 2 CF 2 CF 2 O) a CF 2 CF 2 —;

(vi) —CF 2 CF 2 O[CF(CF 3 )CF 2 O] a CF 2 CF 2 —;

(vii) —CF 2 O(CF 2 CF 2 O) a (CF 2 O) b CF 2 —; or

(viii) —CF 2 O(CF 2 CF 2 O) a CF 2 —;

or a combination thereof;

wherein each a is, independently from 1 to 20, and

wherein each b is independently from 1 to 20.

17 . The lubricant of claim 1 , comprising a weight average molecular weight from about 0.1 to 20 kiloDaltons (kDa).

18 . 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.

19 . 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.

20 . A data storage system, comprising:

a slider comprising at least one magnetic head and an air bearing surface (ABS), wherein a lubricant according to claim 1 is disposed on the ABS; and

the 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).

21 . A lubricant comprising: a plurality of segments according to general formula (I), (II), or (III):

Re 1 —Rb 1 -Rc-Rb 2 —Re 2   (I);

Re 1 —Rb 1 —Re 2   (II); or

Re 1 —Rb 1 —(Rc-Rb 2 ) m -Re 2   (III);

wherein Rc is a divalent linking segment that optionally includes a first anchoring functional group;

wherein each Rb 1 and Rb 2 independently comprises a chain segment comprising at least one of a fluoroalkyl ether moiety, a fluoroalkenyl ether moiety, a perfluoroalkyl ether moiety, a perfluoroalkenyl ether moiety, or a combination thereof;

wherein each of Re 1 and Re 2 independently comprises a group having a higher rotational energy barrier than that of CH 2 , terminating with at least one second anchoring functional group engageable with the protective overcoat of the magnetic recording medium comprising —CH 2 OCH 2 (CH 2 ) n (Ra) n-1 or —OCH 2 (CH 2 ) n (Ra) n-1 , wherein Ra is the second anchoring functional group, m=2 and n=2-10.