JP3527938B2 - A thermosensitive material using a polymer gel in which the density of a network structure using a liquid crystalline polymer is controlled, and a method for producing the same. - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive body using a polymer gel compound in which a density of a network structure is controlled using a lyotropic liquid crystalline polymer, and a method for producing the same. More specifically, a bifunctional monomer, an N-substituted acrylamide containing a polymerization initiator, an N-substituted methacrylamide, or a liquid crystal polymer exhibiting a lyotropic liquid crystal phase is dissolved in a mixed solvent of these monomers and a solvent to form a liquid crystal phase. The present invention relates to a heat-sensitive body using a polymer gel in which the density of the network structure corresponding to the liquid crystal structure is controlled by heat-polymerizing after forming the polymer, and then removing the liquid crystalline polymer, and a method for producing the same. .

[0002]

[Prior Art] In recent years, temperature, solvent, pH, salt concentration, electric field,
Research on stimuli-responsive polymer gels that reversibly expand and contract due to changes in the external environment such as light is being actively conducted. Among them, poly (N-isopropylacrylamide) gel, poly (N-
Poly (N) such as normal propyl acrylamide gel
Poly (N-substituted methacrylamide) gels such as -substituted acrylamide) gels, poly (N-isopropylmethacrylamide) gels, and poly (N-normalpropylmethacrylamide) gels are called thermosensitive polymer gels and have a lower criticality. The physical properties change at the solution temperature. These gels swell in water below the lower critical solution temperature and shrink above. The gel is hydrophilic in the swollen state and hydrophobic in the contracted state. In recent years, artificial muscle models, actuators, drug delivery systems, and the like, which utilize changes in the physical properties of these gels, have been proposed and attempts have been made for their implementation. These thermosensitive polymer gels are generally synthesized by radical polymerization or γ-ray crosslinking,
The polymer network that constitutes the gel is isotropic, and there is no example in which its fine structure is controlled.

Tsutsui et al. Dissolved poly (γ-butyl L-glutamate) in butyl acrylate containing a cross-linking agent,
After forming a cholesteric liquid crystal phase, polymerization is carried out to obtain a poly (butyl acrylate) -poly (γ-butyl L-glutamate) complex which retains the liquid crystal phase. Removal of poly (γ-butyl L-glutamate) from the complex using strong acid gave poly (butyl acrylate) gel with fingerprint-like texture (T. Tsutsui, T. Tanaka, Polymer, 2
2, 117 (1981)). However, it has not been reported that the poly (butyl acrylate) gel is a polymer gel that expands and contracts reversibly with heat and temperature.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a heat sensitive body using a lyotropic liquid crystalline polymer and a gel in which the density of the polymer network at a fine level is controlled, and a method for producing the same. To do.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies on a method for controlling the density of a polymer network at a fine level in a polymer gel, and as a result, have found that a bifunctional monomer and a polymerization initiator have been added. Contains N-isopropylacrylamide, N-
N-substituted acrylamide such as normal propyl acrylamide), N-isopropyl methacrylamide, N-
By dissolving a lyotropic liquid crystal polymer in an N-substituted methacrylamide such as normal propyl methacrylamide or a mixed solution of these monomers and a solvent to form a liquid crystal phase and then polymerizing it, and then removing the liquid crystalline polymer. The present inventors have found that a polymer gel in which the density of a polymer network is controlled at a fine level has thermoresponsiveness, and based on this finding, the present invention has been completed.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION A polymer having lyotropic liquid crystallinity is dissolved in a monomer mixture containing an N-substituted acrylamide derivative and / or an N-substituted methacrylamide derivative and a bifunctional monomer and, if necessary, a solvent to obtain a liquid crystal structure. After the formation of semi-IP, it is polymerized to retain the liquid crystal structure.
Get N. Semi-IPN is an interpenetrating network consisting of cross-linked polymer and non-cross-linked polymer. Semi-IPN is washed with a large excess of solvent to remove liquid crystalline polymer and then immersed in water. Then, a polymer gel in which the density of the polymer network at a fine level corresponding to the liquid crystal structure is controlled can be obtained. This polymer gel is responsive to heat and temperature, as will be described later. The polymer showing a lyotropic liquid crystal phase used in the present invention includes a polypeptide, a cellulose derivative, DNA and the like. Also,
As the bifunctional monomer used in the present invention,
Examples include N, N-methylenebisacrylamide, ethylene glycol dimethacrylate, and divinylbenzene.
N, N-methylenebisacrylamide is particularly preferable. Furthermore, as the solvent used in the present invention, dimethyl sulfoxide, N, N-dimethylformamide,
There are 1,4-dioxane and water. Dimethyl sulfoxide is particularly preferable.

[0007]

Example N-N-propylacrylamide containing 0.8 mg of N, N'-methylenebisacrylamide (crosslinking agent) and 0.8 mg of 2,2'-azobis (isobutyronitrile) (polymerization initiator) (Vinyl monomer): 574m
g, dimethyl sulfoxide (solvent): 378 mg of a mixed solution of poly (γ-methyl L-glutamate-L-glutamic acid) copolymer (saponification rate: 73.3%) (liquid crystal polymer): 126 mg, and dissolved at room temperature to 1 I left it on the day. After the lyotropic liquid crystal phase was completely formed, polymerization was carried out at a temperature of 60 ° C. for 24 hours. Semi-IPN transparent by polymerization
(Poly (N-n-propylacrylamide) gel-poly (γ-methyl L-glutamate-L-glutamic acid) copolymer complex) gel was obtained. When observed with a polarizing microscope, the fingerprint structure shown in FIG. 1 was observed.

The cholesteric half pitch of the semi-IPN (line width, width between striped lines) was 0.87 μm. Next, the semi-IPN was immersed in N, N-dimethylformamide for 1 to 2 weeks to remove unreacted monomer and poly (γ-methyl L-glutamate-L-glutamic acid) copolymer. The gel swollen in N, N-dimethylformamide was immersed in water and the solvent was replaced with water. Although the birefringence of the poly (N-n-propylacrylamide) gel was lowered, the fingerprint-like tissue shown in FIG. 2 was retained. The line width of the striped pattern at this time was 1.12 μm. By removing the poly (γ-methyl L-glutamate-L-glutamic acid) copolymer, high and low mesh density regions were regularly formed inside the poly (N-n-propylacrylamide) hydrogel. It is considered that the tissue was observed.

Poly (N-n-propylacrylamide)
The hydrogel exhibits thermosensitive response in water, and swells at a temperature of 21 ° C or lower and contracts at a temperature of 21 ° C or higher. Therefore, the change in the degree of swelling of the gel due to the temperature change was compared between the poly (N-n-propylacrylamide) hydrogel gel synthesized by the usual radical polymerization method and the poly (N-n-propylacrylamide) hydrogel synthesized in the liquid crystal. . Poly (N-n-propyl acrylamide) hydrogel synthesized by radical polymerization shrinks with increasing temperature, 21 ℃
It became constant in the vicinity. It was found that the gel synthesized in the liquid crystal had a shrinking temperature slightly shifted to the high temperature side, but contracted as the temperature increased. The line width of the striped pattern also reversibly changed with the expansion and contraction, and the gel pattern (striped pattern) also reversibly changed. The result is shown in FIG. Since the gel pattern (striped pattern) changes with temperature, it can be applied to a sensor or the like that detects the temperature by identifying the gel pattern (striped pattern). Further, by utilizing the phenomenon that the pattern changes with temperature, it is possible to realize a lens, an optical element, or the like that can reversibly change the refractive index with temperature.

[0010]

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to efficiently produce a novel thermosensitive polymer gel in which the density of the polymer network at a fine level corresponding to the liquid crystal structure is controlled. This gel not only reversibly expands and contracts due to temperature changes, but also reversibly changes the line width and pattern (striped pattern) of the striped pattern, so lenses and optical elements whose refractive index can be controlled by temperature,
Alternatively, it may be applied to a sensor that recognizes temperature according to a pattern or the like.

[0011]

[Brief description of drawings]

FIG. 1 is a polarization micrograph of a fingerprint-like tissue. (Submit the original version separately)

FIG. 2 is a polarization micrograph of the fingerprint-like tissue after removing the lyotropic polymer. (Submit the original version separately)

FIG. 3 is a characteristic diagram showing the expansion and contraction behavior of the gels synthesized in Examples according to temperature changes.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI G02F 1/13 102 G02F 1/13 102 // C08L 33:24 C08L 33:24 (56) Reference JP-A-6-228215 ( JP, A) JP 10-316453 (JP, A) JP 60-110777 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C09K 3/00 C08F 2/44 C08F 20/54-20/60 C08J 9/26-9/26 102 G02F 1/16 102-1/141 C08L 33/24-33/26

Claims (5)

(57) [Claims] 1. A liquid crystal structure is formed by dissolving a polymer having lyotropic liquid crystallinity in a monomer mixture containing an N-substituted acrylamide derivative and / or an N-substituted methacrylamide derivative and a bifunctional monomer and, if necessary, a solvent. A heat-sensitive body using a polymer gel compound obtained by polymerizing and then removing a lyotropic liquid crystalline polymer after being formed. 2. The heat-sensitive body according to claim 1, wherein a pattern of a fingerprint-like structure formed by the polymer gel compound is used for temperature detection. 3. The heat-sensitive body according to claim 1, which is an optical element made of a polymer gel compound. 4. A liquid crystal structure is formed by dissolving a polymer showing lyotropic liquid crystallinity in a monomer mixture containing an N-substituted acrylamide derivative and / or an N-substituted methacrylamide derivative and a bifunctional monomer and, if necessary, a solvent. A method for producing a heat-sensitive body using a polymer gel compound obtained by forming, then polymerizing, and removing a lyotropic liquid crystalline polymer. 5. The method for producing a heat-sensitive body according to claim 4, wherein the monomer mixture contains a polymerization initiator.