Provided is a lubricity-imparting agent that can impart durable lubricity (in particular, lubricity at the time of wetting) to a substrate. It has been found that a lubricity-imparting agent including a copolymer containing a constitutional unit (A) based on 2-methacryloyloxyethyl phosphorylcholine and a constitutional unit (B) based on a photoreactive functional group-containing monomer, or a copolymer containing a constitutional unit (A) based on 2-methacryloyloxyethyl phosphorylcholine, a constitutional unit (B) based on a photoreactive functional group-containing monomer, and a constitutional unit (C) based on a hydrophobic group-containing monomer can impart durable lubricity to a substrate surface through a simple approach called photoirradiation.

Provided is a lubricity-imparting agent that can impart durable lubricity (in particular, lubricity at the time of wetting) to a substrate. It has been found that a lubricity-imparting agent including a copolymer containing a constitutional unit (A) based on 2-methacryloyloxyethyl phosphorylcholine and a constitutional unit (B) based on a photoreactive functional group-containing monomer, or a copolymer containing a constitutional unit (A) based on 2-methacryloyloxyethyl phosphorylcholine, a constitutional unit (B) based on a photoreactive functional group-containing monomer, and a constitutional unit (C) based on a hydrophobic group-containing monomer can impart durable lubricity to a substrate surface through a simple approach called photoirradiation.

A hydrophilic copolymer that can form a surface lubricious layer exhibiting superior lubricating property and durability (lubrication retaining property), is provided. A hydrophilic copolymer having a good solvent solubility is provided. A hydrophilic copolymer is provided containing: structural units derived from a polymerizable monomer (A) having a sulfobetaine structure; structural units derived from a polymerizable monomer (B) having at least one group selected from the group consisting of a sulfonic acid group (SO.sub.3H), a sulfuric acid group (OSO.sub.3H), a sulfurous acid group (OSO.sub.2H), and groups of salts thereof; and structural units derived from a polymerizable monomer (C) having a photoreactive group.

A hydrophilic copolymer that can form a surface lubricious layer exhibiting superior lubricating property and durability (lubrication retaining property), is provided. A hydrophilic copolymer having a good solvent solubility is provided. A hydrophilic copolymer is provided containing: structural units derived from a polymerizable monomer (A) having a sulfobetaine structure; structural units derived from a polymerizable monomer (B) having at least one group selected from the group consisting of a sulfonic acid group (SO.sub.3H), a sulfuric acid group (OSO.sub.3H), a sulfurous acid group (OSO.sub.2H), and groups of salts thereof; and structural units derived from a polymerizable monomer (C) having a photoreactive group.

A lubricating system includes a machine configured to operate in a first operating state and a second operating state; and a heat activated polymer material applied to at least a part of the machine and to remain solid during the first operating state and to soften upon being heated in the second operating state to lubricate the machine. The heat activated polymer material may soften due to increased friction incurred by the machine in the second operating state. A heating element may be operatively connected to any of the machine and the heat activated polymer material. The heat activated polymer material may soften due to being heated by the heating element in the second operating state. An injector may apply the heat activated polymer material to the machine. A channel may direct a flow of the heat activated polymer material as it softens in the second operating state.

A lubricating system includes a machine configured to operate in a first operating state and a second operating state; and a heat activated polymer material applied to at least a part of the machine and to remain solid during the first operating state and to soften upon being heated in the second operating state to lubricate the machine. The heat activated polymer material may soften due to increased friction incurred by the machine in the second operating state. A heating element may be operatively connected to any of the machine and the heat activated polymer material. The heat activated polymer material may soften due to being heated by the heating element in the second operating state. An injector may apply the heat activated polymer material to the machine. A channel may direct a flow of the heat activated polymer material as it softens in the second operating state.

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.

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.

A mixture of polymers with lubricating properties is provided. The polymer can be used to produce a lubricating fluid. They can also be born on a surface or embedded in a porous material. This mixture of polymers comprises (a) a pharmaceutically acceptable bottle-brush polymer comprising a backbone with polymeric pendant chains, and (b) a pharmaceutically acceptable linear polymer. In the lubricating fluid, the bottle-brush polymer and the linear polymer are dissolved together in a pharmaceutically acceptable solvent.

A mixture of polymers with lubricating properties is provided. The polymer can be used to produce a lubricating fluid. They can also be born on a surface or embedded in a porous material. This mixture of polymers comprises (a) a pharmaceutically acceptable bottle-brush polymer comprising a backbone with polymeric pendant chains, and (b) a pharmaceutically acceptable linear polymer. In the lubricating fluid, the bottle-brush polymer and the linear polymer are dissolved together in a pharmaceutically acceptable solvent.