BR102019003067A2 - POLYMERIC BLEND OF THE SEMI-IPN TYPE BASED ON POLYACRYLATES AND POLYELETROLYTES - Google Patents

Abstract

the semi-ipn polymer blend based on polyacrylate polymers as polyelectrolyte is an invention with potential use as an actuator, electromechanical or thermoelectric generator, motion, pressure and temperature sensor, representing an advance in the use of devices in the field of polymer blends. its electrical generation capacity can be explored from mechanical and thermal stimuli, as well as take advantage of this electricity to identify and measure mechanical, thermal changes or flexion and extension movements, expanding its applications in numerous activities in the biomedical, physical, chemical areas, among others. when an electric voltage is applied in direct current, the blend produces movement, when disposed between two flexible electrodes superimposed on the film. when mechanical pressure is applied to the blend, a difference in electrical potential is generated on the faces of the polymeric film, and this electricity can be stored, used as a mechanical motion sensor, pressure sensor or shock absorber-generator, in addition to the initial actuator functions . the variant actions presented in the tests described in this patent suggest that this blend can be used in the biomedical, aerospace, mechanical, electrical, electronic, robotics areas, among several other applications.

Description

POLYMERIC BLEND OF THE SEMI-IPN TYPE BASED ON POLYACRYLATES AND POLYELETROLYTES FIELD OF THE INVENTION

[001] Intelligent polymers are materials capable of responding to a stimulus, presenting physical or chemical changes in their behavior, having biomedical, industrial, pharmaceutical, food, hardware, electronics applications, among others. The present invention describes a mixture of ionic polymers in the form of a polymer blend of the semi-IPN type based on polyacrylates and linear or branched polyelectrolytes. This blend demonstrated variant functions according to the type of stimulus (electrical, mechanical or thermal). When an electric voltage is applied in direct current, the blend produces movement, when disposed between two flexible electrodes superimposed on the film. When mechanical pressure is applied to the blend, a difference in electrical potential is generated on the faces of the polymeric film, and this electricity can be stored, used as a mechanical motion sensor, pressure sensor or shock absorber-generator, in addition to the initial actuator functions . It also has thermoelectric potential as a temperature sensor and thermoelectric generator.

PREVIOUS

[002] In conventional synthesis of hydrogels of acrylate polymers, free radical polymerization is used, from activated vinyl monomers such as acrylic acid, methacrylic acid, 2-hydroxyethyl methacrylate; acrylamide, methacrylamide, N-Isopropyl acrylamide, diacetone acrylamide, N, N-dimethylacrylamide, 2-hydroxyethylmethacrylamide, 2-Acrylamide-2-methylpropane-sulfonic acid. For this purpose, crosslinking agents such as N, N-methylene bisacrylamide, ethylene diacrylate, ethylene glycol dimethacrylate, 1,1,1-trimethylol-propanotriacrylate, methacryloxyethyl vinyl carbonate, trialylamine and tetra (allyloxy) ethane (KÜNZLER) are used , Jay Friedrich. Hydrogels. Encyclopedia of polymer science and technology, v. 2, p.691-722, 2002; BUCHHOLZ, Fredric L. Superabsorbent polymers. Encyclopedia of Polymer Science and Technology, v. 8, pp. 106- 121, 2002). Although these hydrogels are used in the composition of superabsorbent materials and as smart polymers, there is no description of their use as part of actuators, generators and polymeric sensors.

[003] Polyelectrolytes are polymers that present a charge when they are solubilized or immersed in a highly polar liquid such as water. This category includes poly (acrylic acid), (6,6-ionene) N, poly (2-vinyl-pyridine), poly (lysine), poly (diallyldimethylammonium chloride), poly (dimethylaminoethyl acrylate), poly (methacrylic acid), poly (ethylene imine), poly (styrene sulfonic acid), poly (glutamic acid), poly (vinyl sulfate), poly (acrylamide-co-acrylic acid), hyaluronic acid, chitosan, carboxymethyl cellulose and DNA (single strand) (HOAGLAND, David. Polyelectrolytes. Encyclopedia of Polymer Science and Technology, v.7, p.439-504, 2002). However, the combined use of these two categories of materials (polyacrylates and polyelectrolytes) have not been described for obtaining actuators, generators and polymeric sensors.

[004] Electroactive polymers have, among other specificities, a movement mechanism based on ionic migration within the polymeric mesh (UK, Jie et al., Smart Materials and Structures, v. 27, n. 2, p. 02LT01, 2018). Some of these materials still have the ability to produce a difference in electrical potential when heated on one of their faces / ends (CULEBRAS, Mario; GÓMEZ, Clara M .; CANTARERO, Andrés. Materials, v. 7, n. 9, p . 6701-6732, 2014.).

[005] This class of materials has been studied for use in the medical-hospital industry, producing artificial muscles (TOLBAH, Farid A. et al, Research and Education in Mechatronics (REM), 2014 15th International Workshop on. IEEE, 2014. p 1-7.), Ventricular orthoses (HOSSEINIPOUR, M .; ELAHINIA, M., Bioinspiration, Biomimetics, and Bioreplication 2013. International Society for Optics and Photonics, 2013. p. 86860M.), Targetable catheter (YOON, W Jong; REINHALL, Per G .; SEIBEL, Eric J., Sensors and Actuators A: Physical, v. 133, n. 2, p. 506-517, 2007.). However, no polyacrylate associated with a polyelectrolyte in the form of a polymer blend has yet been described.

[006] Studies in the area of sensors and actuators point to the predominant use of a perfluorinated sulfonated polymer as a material that allows the exchange of ions, making it the standard material for such uses (CHATTARAJ, Ritwik et al., Sensors and Actuators A : Physical, v. 270, p. 65-71, 2018). However, no mention of the use of polyacrylate associated with a polyelectrolyte in a polymer blend has been cited in the literature.

[007] The patent US2015287906 (A1) with the title of POLYMER BLENDS OF ELECTROSTRICTIVE TERPOLYMER WITH OTHER POLYMERS on the date 2009-10-15 describes an actuator that makes use of a polymer blend based on polyvinylidene fluoride added to a terpolymer derived from polyvinylidene fluoride or polyvinyl fluoride. However, this invention limits the production methodology to a multilayer blend and does not cover the thermoelectric use of the polyacrylate blend associated with a polyelectrolyte.

[008] US6475639B2 with the title IONIC POLYMER SENSORS AND ACTUATORS describes the production method for a device with multiple applications based on a composite consisting of a sulfonated perfluorinated polymer film and chemically deposited lithium electrodes to be used as a sensor for movements or actuator, not covering the use of a thermoelectric or pressure sensor of the polyacrylate blend associated with a polyelectrolyte.

[009] Like devices with sensor and actuator function, a graphene and polyaniline composite was developed (KHMELNITSKIY, Ivan K. et al., Young Researchers in Electrical and Electronic Engineering. IEEE, 2018. p. 419-422) . As an actuator and generator, a sulfonated and silver perfluorinated polymer was used (ZHAO, Yang et al., Polymers (20734360), v. 10, n. 7, 2018). As a thermoelectric generator, a composite based on polyetherimide and carbon nanotubes was used (TZOUNIS, Lazaros et al., Composites Science and Technology, v. 156, p. 158-165, 2018). As a thermal sensor, polyvinylfluoridene was used (PARKER, Adrian et al., Journal of Polymer Science & Applications, v. 2018, 2018) or as a pressure sensor, a composite based on polyimide and carbon nanotubes (NELA, Luca et al., Nano letters, v. 18, n. 3, p. 2054-2059, 2018). In none of these works was a polymer blend based on polyacrylate associated with a polyelectrolyte. The experiment using polyacrylamide associated with sodium chloride to form an ionic hydrogel (KEPLINGER, Christoph et al., Science, v. 341, n. 6149, p. 984-987, 2013), showed a response under high electrical voltage (above 3 kV), making it not viable for several practical uses, and no polymer blend or composite is produced using a polyacrylate associated with a polyelectrolyte.

[010] There are no published studies in the area where intelligent polymers exercise simultaneously with the multiple functions of actuator, electromechanical generator, thermoelectric generator, thermal and pressure sensor. All the works presented so far do not use a single material with the simultaneous function of an actuator, electromechanical generator or mechanical sensor, nor do they use a polymer blend based on polyacrylates and polyelectrolytes.

GENERAL DESCRIPTION

[011] The present invention describes the production of a semi-IPN polymer blend (Figure 1) used as an actuator, flexogelelectric generator, thermoelectric generator, mechanical sensor and temperature sensor. Figure 1 graphically represents the organization of a polymer blend of the semi-IPN type, where the base polymer is polyacrylamide (Figure 1-A), or another polymer in the group of acrylates of the hydrogel type that is formed by the action of a crosslinking agent (Figure 1-B), and a second polymer, sodium poly-4-styrenesulfonate, or another straight-chain polymer of the polyelectrolyte type (Figure 1-C). The polymeric film is in the form of a hydrogel, whose chain cross-linked (Figure 2) retains the linear chain polymer, together with solvated water, within its mesh. Such architecture allows the migration of the polyelectrolyte, the solvated water, as well as the salt added to the precursor solution of the blend, according to the electric field, movement or temperature applied to the film. For the synthesis of the cross-linked polymer (Figure 2), a polyaddition reaction of the sol-gel type where acrylamide (or other hydrophilic mere of the acrylate family) (Figure 2-A) react with each other and with the bis-acrylamide crosslinking agent (or other crosslinking agent) (Figure 2- B) and the consequent production of the cross-linked polyacrylamide (Figure 2-C). The linear polymer of the polyelectrolyte type (in this case the sodium poly-4-styrenesulfonate) (Figure 3) of the semi-IPN system is added before the reaction initial, which may have cationic (Figure 3-A) or anionic (Figure 3-B) properties.

PREFERRED EMBODIMENTS

[012] Production of the polymer blend of the semi-IPN type, made with polyacrylamide as the base polymer and sodium poly-4-styrenesulfonate as the thermoplastic fraction. For this purpose, Acrylamide, Bis-Acrylamide, Sodium Poly-4-styrenesulfonate, Sodium Chloride, Water type I, Sodium Persulfate and TEMED were used, whose quantities define the physicochemical variations of the blend. The reagents are added in the order described above, being mixed until completely homogenized. Finally, TEMED is added in order to allow its action as a catalyst for the polyaddition reaction of acrylamide with bis-acrylamide, trapping sodium poly-4-styrenesulfonate in its polymeric mesh, forming the blend initially described as the quantities that can be used. are the following:. between 0.355 and 35.5 g of acrylamide (monomer) · between 0.01277 and 1.927 g of N, N'-methylenebisacrylamide - bis-acrylamide (cross-linker) · 1,000 μL of solution between 1% and 30% poly Sodium -4-styrenesulfonate (ionic polymer) • 250 μL of solution less than 6.16 mol.L-1 of Sodium Chloride (salt) · between 1.0422 and 104.22 mL of type I water (solvent) · 1,328 μL of solution between 1% and 54.5% of sodium persulfate (oxidizing agent) · between 1 and 100 μL of Tetramethylenediamine - TEMED (catalyst for the addition reaction). The device obtained through the elaboration of the polymeric film presented characteristics physical and chemical properties that allow its use as an actuator when associated with electrodes on their faces.

[013] With the addition of a suspension containing graphite powder in the making of the blend, replacing type I water, as described in mode 1, this composite starts to behave as an electrode with low electrical resistance.

[014] The blend produced in the first preferred modality is made in the format of polymeric film and associated with flexible electrodes of the type metallic foils, for example, aluminum and gold, generating an actuator and generator type device. The produced material presents great deformation in the presence low electrical voltage (Figure 4) and low impedance. Electrically, it has the behavior of a Capacitive-Resistive circuit. Figure 4 represents a perspective sketch of a device with actuator, generator and sensor functions, based on the polymeric blend of the Semi-IPN type produced. Where you can see a conductive film (4-A) and a solid electrolytic polymer (4-B) and the type of movement after electrical excitation as an actuator (4-C). The movement of the device occurred after using a fixed coupled support two electrodes connected to a DC voltage source, with manual reversal. FIGURE 5 represents the movement presented by the developed device. Its ability to move is observed when exposed to low voltages, starting from rest at 0 V (5-A), 8.4 V (5-B) and -8.4 V (5-C). The device had a reversible movement with an amplitude greater than 3 cm, under a voltage of 8.4 V.

[015] The device described in the third preferred modality presents electrical voltage when moved, thus characterizing the flexogelelectric effect, producing a potential difference in its electrodes after being moved mechanically.

[016] The device described in the third preferred mode has a 'Seebeck' effect after being heated to about 69 ° C, with a voltage peak of 1,675 mV, which voltage can be stored, used to power microdevices or as a temperature sensor .

[017] The material has capacitance compatible with other functionalities other than a capacitor. Such as the maintenance of constant low electrical voltages, equivalent to a cell or electrochemical battery. When being electrically excited with a voltage of 5 Vac, at 30 Hz, the blend raises the circuit voltage (voltage source coupled to a voltage follower) in which it is inserted to 50 Vac (peak to peak).

Claims (9)

Polymeric blend of the semi-IPN type based on polyacrylates and polyelectrolytes, characterized by using acrylate monomers for formation and crosslinking of the polymeric chain, linear or branched chain polyelectrolyte and salts for the manufacture of hydrogel-type blends. Polymeric blend of the semi-IPN type based on polyacrylates and polyelectrolytes, characterized by synthesis using acrylamide / bisacrylamide as cross-linked polyacrylamide and sodium poly-4-styrenesulfonate as linear chain polyelectrolyte for the manufacture of hydrogel-type blends. Polymeric blend of the semi-IPN type based on polyacrylates and polyelectrolytes according to claim 1 or 2, characterized by the addition of graphite powder suspension for the manufacture of conductive composite. Polymeric blend of the semi-IPN type based on polyacrylates and polyelectrolytes according to claim 1 or 2, characterized by being synthesized in the form of films and associated with flexible electrodes for the production of electro-mechanical devices. Polymeric blend of the semi-IPN type based on polyacrylates and polyelectrolytes according to claim 1 or 2, characterized by being synthesized in the form of films and associated with flexible electrodes for electromechanical tactile sensor. Polymeric blend of the semi-IPN type based on polyacrylates and polyelectrolytes according to claim 1 or 2, characterized by being associated with electrodes for the production of generator-type devices. Polymeric blend of the semi-IPN type based on polyacrylates and polyelectrolytes according to claim 1 or 2, characterized by being associated with electrodes for the production of temperature sensors. Polymeric blend of the semi-IPN type based on polyacrylates and polyelectrolytes according to claim 1 or 2, characterized by being associated with electrodes for the production of thermoelectric generators. Polymeric blend of the semi-IPN type based on polyacrylates and polyelectrolytes according to claim 1 or 2, characterized by having capacitive properties, when associated with electrodes, for the production of a device equivalent to an electrochemical battery.

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