The present invention provides a fluorine-containing ether compound represented by the following formula:
R.sup.1R.sup.2CH.sub.2R.sup.3CH.sub.2R.sup.4R.sup.5
(in the formula, R.sup.3 represents a perfluoropolyether chain; R.sup.1 and R.sup.5 each independently represent any of an alkyl group which may have a substituent, an organic group having a double bond or a triple bond, and a hydrogen atom; R.sup.2CH.sub.2R.sup.3 is represented by -[A]-[B]OCH.sub.2R.sup.3; R.sup.3CH.sub.2R.sup.4 is represented by R.sup.3CH.sub.2O[C]-[D]-; [A] is represented by Formula (4), [B] is represented by Formula (5), [C] is represented by Formula (6), and [D] is represented by Formula (7)): ##STR00001##

High temperature lubricants for magnetic media are provided. One such lubricant includes fluoroalkyl, fluoroalkenyl, perfluoroalkyl, or perfluoroalkyl ether segments, anchoring functional groups engageable with a protective overcoat of a magnetic recording media, and cyclic functional groups. The lubricants can be used in conjunction with a magnetic recording medium and/or a magnetic data storage system.

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.

Provided are a lubricant that is highly resistant to contamination and highly thermally stable, a lubricant that is highly durable and highly heat resistant, and a magnetic disk. A fluoropolyether compound contains perfluoropolyether groups, end groups each containing at least one hydroxyl group, and a linking group that is comprised of a C.sub.4-C.sub.14 hydrocarbon group and that contains at least one hydroxyl group.

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.

An electrorheological fluid which comprises a dispersion medium containing fluorine atoms in an amount larger than 0 wt % but not larger than 50.0 wt % and particles for electrorheological fluid use that are contained in the dispersion medium in an amount of 10-50 vol % of the total volume of the dispersion medium and the particles, the particles comprising a sulfonic-acid-group-containing polymer having a sulfonic acid group content of 30-70 wt %.

A fullerene derivative of the present invention has a fullerene skeleton and a plurality of perfluoropolyether chains in a molecule, wherein the perfluoropolyether chains are bonded to the fullerene skeleton via methano groups, and a lubricant and fluororesin composition of the present invention contain the derivative.

In one embodiment, a multidentate perfluoropolyether (PFPE) lubricant has the formula S.sub.e-S.sub.o-S.sub.i-S.sub.L-S.sub.i-S.sub.o-S.sub.e, where each S.sub.o includes at least one perfluoroethyl ether unit, S.sub.L is a linker segment, and each S.sub.e and S.sub.i include at least one functional group configured to attach to a surface. In another embodiment, a multi dentate PFPE lubricant has the formula S.sub.e-S.sub.o(a)-S.sub.i-S.sub.m-S.sub.i-S.sub.o(b)-S.sub.e, where each S.sub.o(a), S.sub.o(b), and S.sub.m include at least one perfluoroethyl ether unit with the proviso that S.sub.m has a different number of perfluoroethyl ether units than at least one of So.sub.(a) and S.sub.o(b), and each S.sub.e and S.sub.i include at least one functional group configured to attach to a surface.

The disclosure relates to a substrate comprising a surface at least part of which is coated with an epilamization agent, the epilamization agent including at least one compound in the form of a block copolymer comprising at least one block of M units linked by covalent bonds by their main chains, and at least one block of N units linked by covalent bonds by their main chains, the blocks being connected to each other by covalent bonds by their main chains in linear sequences, where M is a and N is ##STR00001##

In an organic fluorine compound, an organic group including a single aromatic ring or a condensed ring consisting of aromatic rings at a non-bonded terminal is bonded to each of all of terminals of a chain structure including a perfluoropolyether structure.