A photocurable coraposition can comprise a polyme.aizable material and a photoinitiator, wherein the polymerizahle material can comprise at least one acrylate monomer including at least one cyano group (CN-acrylate monomer). The presence of a low amount of the CN-acrylate monomer between 10 wt% and not greater than 30 wt% can lower the contact angle of the composition and may improve the etch resistance of a photo-cured layer made from the photocurable composition.

A photocurable coraposition can comprise a polyme.aizable material and a photoinitiator, wherein the polymerizahle material can comprise at least one acrylate monomer including at least one cyano group (CN-acrylate monomer). The presence of a low amount of the CN-acrylate monomer between 10 wt% and not greater than 30 wt% can lower the contact angle of the composition and may improve the etch resistance of a photo-cured layer made from the photocurable composition.

A polymer electrolyte includes a polymer matrix including a polymer having a repeating unit represented by the formula

##STR00001##

and an ionic liquid. R.sup.1 to R.sup.3 are each one of a substituted or unsubstituted C.sub.1-C.sub.12 alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or combinations thereof. Each R.sup.4 is one of hydrogen, a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C.sub.1-C.sub.10 alkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted C.sub.5-C.sub.14 heteroaryl group, or combinations thereof. Substituents of R.sup.1 to R.sup.4 are each one of a halogen group, a cyano group, a nitro group, a C.sub.1-C.sub.8 alkyl group, or combinations thereof, x is an integer of 1 to 8, and n is an integer of 60 to 3200.

A resin composition for secondary coating of an optical fiber contains a photopolymerizable compound and a photopolymerization initiator, wherein the photopolymerizable compound contains: a urethane (meth)acrylate that is a reaction product of a polyol having a number average molecular weight of 300 or more and 1200 or less, a diisocyanate, and a hydroxyl group-containing (meth)acrylate; a bisphenol skeleton-containing (meth)acrylate; and a monofunctional (meth)acrylate in which a glass transition temperature of a homopolymer of the monofunctional (meth)acrylate is −60° C. or more and 15° C. or less; and when the resin composition is ultraviolet-cured under conditions of an accumulated amount of light of 1000 mJ/cm.sup.2 and an illumination of 1000 mW/cm.sup.2 to form a resin film, the Young's modulus of the resin film is 1200 MPa or more and 3000 MPa or less at 23° C., and the glass transition temperature of the resin film is 70° C. or more and 105° C. or less.

A resin composition for secondary coating of an optical fiber contains a photopolymerizable compound and a photopolymerization initiator, wherein the photopolymerizable compound contains: a urethane (meth)acrylate that is a reaction product of a polyol having a number average molecular weight of 300 or more and 1200 or less, a diisocyanate, and a hydroxyl group-containing (meth)acrylate; a bisphenol skeleton-containing (meth)acrylate; and a monofunctional (meth)acrylate in which a glass transition temperature of a homopolymer of the monofunctional (meth)acrylate is −60° C. or more and 15° C. or less; and when the resin composition is ultraviolet-cured under conditions of an accumulated amount of light of 1000 mJ/cm.sup.2 and an illumination of 1000 mW/cm.sup.2 to form a resin film, the Young's modulus of the resin film is 1200 MPa or more and 3000 MPa or less at 23° C., and the glass transition temperature of the resin film is 70° C. or more and 105° C. or less.

The present invention relates to a water-soluble polymer obtained by polymerization of at least a 2-dimethylaminoethyl acrylate monomer and/or its salts, in presence of at least a tocopherol and/or its derivatives, or a tocotrienol and/or its derivatives, and its uses.

The present invention relates to a water-soluble polymer obtained by polymerization of at least a 2-dimethylaminoethyl acrylate monomer and/or its salts, in presence of at least a tocopherol and/or its derivatives, or a tocotrienol and/or its derivatives, and its uses.

The present invention provides a polymer-based piezoelectric composite material from which a piezoelectric film capable of outputting a higher sound pressure and exhibiting excellent flexibility even in a low-temperature environment is obtained in a case of using a piezoelectric speaker, a piezoelectric film formed of the polymer-based piezoelectric composite material, and a piezoelectric speaker and a flexible display which are formed of the piezoelectric film. The polymer-based piezoelectric composite material of the present invention is a polymer-based piezoelectric composite material including a polymer matrix which contains a polymer containing a group represented by Formula (1), and piezoelectric particles.

*-L.sup.1-(CR.sup.1R.sup.2).sub.n—CN  Formula (1)

In Formula (1), L.sup.1 represents a divalent linking group excluding a urethane group. R.sup.1 and R.sup.2 each independently represent a hydrogen atom, an alkyl group, or an aryl group. n represents an integer of 3 or greater. * represents a bonding position with respect to the main chain of a polymer.

The present invention provides a polymer-based piezoelectric composite material from which a piezoelectric film capable of outputting a higher sound pressure and exhibiting excellent flexibility even in a low-temperature environment is obtained in a case of using a piezoelectric speaker, a piezoelectric film formed of the polymer-based piezoelectric composite material, and a piezoelectric speaker and a flexible display which are formed of the piezoelectric film. The polymer-based piezoelectric composite material of the present invention is a polymer-based piezoelectric composite material including a polymer matrix which contains a polymer containing a group represented by Formula (1), and piezoelectric particles.

*-L.sup.1-(CR.sup.1R.sup.2).sub.n—CN  Formula (1)

In Formula (1), L.sup.1 represents a divalent linking group excluding a urethane group. R.sup.1 and R.sup.2 each independently represent a hydrogen atom, an alkyl group, or an aryl group. n represents an integer of 3 or greater. * represents a bonding position with respect to the main chain of a polymer.

A resin composition includes: a resin having a first group capable of forming at least two hydrogen bonds; and a photoisomerization compound having a second group capable of forming at least two hydrogen bonds complementarily with the first group and having a moiety that is reversibly isomerized by light.