**2. Different manufacturing process of IPMC membrane**

The important pillar for IPMC manufacture procedure is choosing the base ion altercation polymers; those are naturally fabricated from the organic polymers, comprising a permanent ionic group of covalently bonded. In the electrochemical industry, generally well-known ion exchange materials are used that rely on a copolymer of divinylbenzene and styrene. Moreover, the permanent ionic groups are shaped after the completion of polymerisation. The widely held ion altercation materials are alkene of perfluorinated: with lesser length side-chains concluded by ionic groups like Nafion, normally ammonium cations for anion exchange or carboxylate or sulfonate (COO� or SO3�) for exchange of cations. In a perfluorinated compound (PFC), all hydrogen is supplanted by fluorine in the chain of carbon; however, the molecule holds one altered functional group or atom at least. The backbones of large polymer conclude their short side-chains and mechanical strength afford ionic groups that interrelate with water and the transportation of suitable ions. Furthermore, they might generate nano-channels of hydrophilic nature that are called cluster networks. Yu. et al. was fabricated the IPMC polymer matrix using the as follows method. However, in this process, the perfluorinated ion exchange membrane is taken upon that metal is deposited, such as platinum or gold. The IPMC matrix samplings were constructed with the twice depositing of platinum on Nafion–117 [20]. The initial stage is to coarsen the material surface; a) the emery paper is used to scratch the membrane surface for increasing the effective surface area; b) using an ultrasonic cleaner, the membrane is cleaned with preferable water; c) the membrane is dipped and boiled the in aqueous hydrochloric acid, i.e., HCl aqueous of 2 N concentration for 30 minutes to eradicate the ions and impurities in the membrane, d) finally after the rinsing with DI water, the entire membrane is merged in hot deionised (DI) water for up to 30 minutes to eliminate acid and swelling the polymer membrane matrix. The coarsened membrane is kept in deionised water. The subsequent procedure steps are to integrate the ion transportation or altercation capability with the help of a complex metal solution. The platinum amine complex ([Pt(NH3)4]Cl2) aqueous solution is used. Furthermore, when the polymer membrane is submerged, a solution of ammonium hydroxide (5%,1 ml) is added that to neutralise. Store the membrane at room temperature in the solution for more than three hours. Following Yu et al., the third step is primary plating. In this procedure, the complex of platinum cations is decreased to a metallic state as nano-particles form with the help of a prominence-reducing agent. After the rinsed in 180 ml 40°C deionised water, sodium borohydride (2 ml of 5%) is mixed in each 30 min for seven times. Within this arrangement, the temperature is raised progressively to 60°C for 1.5 hours. A smooth Pt particles black layer is coated in the membrane surface. After that, the entire polymer matrix, i.e., the membrane, is again washed with deionised (DI) water and plunge in 0.1 N dilute hydrochloric acid for up to one hour. In the finishing procedure, the secondary layer of plating is completed. This methodology is envisioned to deposit Pt over top of the preliminary surface of Pt to diminish the resistance of the surface. Next, the supplementary quantity of Pt is overlaid with the following methods into the as grow Pt layer. Furthermore, hydroxylamine (6 ml) and 5% hydrochloride solution are added, and 20% of hydrazine solution (3 ml) is mixed in every single 30 minutes interval simultaneously. In this sequential fabrication route, the temperature is elevated to 60°C progressively for four hours; after that, the grey metallic texture

will be coated on the membrane surface. After that, when no platinum ions are there in the solution of plating, the membrane is adequately washed with water and again placed in boiling in 0.1 N hydrochloric acid (dilute) to eliminate the cations of ammonium of the membrane.

#### **2.1 Casting method and silica gel process**

The economically available Nafion film thickness varies in the range of 50 180 μm, though the efficiency of the IPMC differs by thickness, like the rigidity of bending, a field of electric, etc. However, to attain a denser or targeted depth of Nafion membrane irrespective of customised thickness, the entire process is illustrated below. Furthermore, this procedure needs a very controlled tuning of the method's parameters like the specific solvent concentration and temperature; therefore, it has reproductivity issues [21]. The thickness of Nafion may be attuned by the fine-tuning of volume dispersion of the Nafion. The overall fabrication procedure comprises four steps (a) stirring, (b) mixing and (c) thermal treatment, and (d) sonication. Thermal handling enhances the Nafion film's mechanical stiffness. Lastly, the Nafion film must be placed in the hydrogen peroxide solution in boiling state for 1 hour within temperature range 75°C -100°C and then the membrane heated for 1 hour in the deionised (DI) water. Furthermore, the process of casting has been testified to attain higher thickness Nafion IPMC actuators [22]. Moreover, Jung et al. was established a Nafion membrane of controlled pore size with porosity by silica sol–gel methods and etching by hydrofluoric acid [23]. Furthermore, they established an improved metal composite actuator consisting of ionic polymer with the help of Nafion membrane having porosity using the ion exchange procedure and electroless plating. After that, (i) the different Nafion surface possessing membranes were coarsened with sandpaper #1200 grading, and after that, the surface is substantially cleaned by ultrasonication cleaning method and chemically using HCl solution (2.5 N); (ii) for the exchange methods of Pt ion, the membranes were dipped in [Pt(NH3)4]Cl2.xH2O solution (0.2 wt%), and then ultrasonicated for 8 h with 30 min interval; (iii) for the initial reduction methods, an aqueous solution about 180 ml having NH4OH (0.5 ml) solution was arranged, and then the membranes are absorbed in that solution; (iv) 1 wt% (0.5 ml) PVP solution and 2 mL of 5 wt% NaBH4 solution is mixed in each 10 min interval; and (v) while the temperature of the solution is 600°C, the 20 mL of NaBH4 solution (5 wt%) was mixed, and after that PVP solution (0.5 ml 1 wt%) was mixed at intervals of 20 min for four times. Finally, while this method was concluded, the membranes were dipped for 12 h in 0.1 N HCl solutions and then cleaned with deionised (DI) water. Thus, the membranes were accomplished by the Pt ion exchange methods of four cycles and the methods of initial reduction. Also, in the second-reduction methods, an aqueous solution of 280 mL is made that contains [Pt(NH3)4]Cl2.xH2O (400 mg) was executed, and the membrane was dipped in that solution at 400C. Then 3 mL of NH2OH-HCl solution (5 wt%) and 6 mL of NH2NH2.H2O solution (20 wt%) were mixed with each 10 min. After that, the membrane was cleaned with DI water and 0.1 N HCl solutions. Lastly, in cation exchange, the membranes were dipped for 48 h in 1.5 N LiCl solutions (**Figure 1**).

#### **2.2 Nafion-CNT composite based IPMC membrane**

Ijeri et al. have prepared a carbon nanotube and Nafion polymer nanocomposite for combinational electron and proton transportation. The membranes depict the proficiency to permit a separate electron-proton transportation path inside the

*IPMC Based Flexible Platform: A Boon to the Alternative Energy Solution DOI: http://dx.doi.org/10.5772/intechopen.99434*

#### **Figure 1.**

*Schematic representation of the fabrication of Nafion membrane technology incorporated with porosity [23].*

membrane matrix. This feature unfastens new applications in particular membranes like advanced synthetic devices proficient in working sunlight to harvest hydrogen using water splitting. The manufacturing procedure is delineated as follows [24]. First, the needed amounts of MWCNTs and Nafion solution were weighed and put for 20 min in an ultrasonic cleaning bath with water. This provided a uniform dispersal of MWCNTs. The quantities were designed to provide MWCNT (0–5%) on a dry weight basis in nafion. In addition, isopropyl alcohol (1 ml) was mixed to assist in the proper dispersion and wetting of MWCNTs. Whenever the homogenous solution was decanted into petri dishes, it was kept on a furnace, maintaining that it is placed in an equal height levelled flat platform allowing uniform evaporation of solvent for 3 h within ambient conditions. Moreover, the entire setup was then replaced at 40°C and in the oven overnight. Furthermore, the membrane was then moistened with deionised (DI) water for one hour, separating the membrane from the entire setup substrate. Finally, selfsupporting, flexible membranes were fabricated by just detaching them from the entire petri dish. Finally, the membrane was dried again and kept in an oven overnight.

#### **2.3 Fabrication procedure by silver nanolayer in the membrane**

Chung et al. introduce nanopowder of silver for IPMC fabrication membrane, which progresses the adhesion between polymer membrane matrix and metal electrode [25]. The normal methodologies of this process are the nanopowders of silver casting with Nafion polymer trailed by ornamentation and technologies of electroless plating of silver. The IPMC actuator of 5 mm (width) x 2 cm (length) x 0.23 mm (thickness) is taken for deformation investigation. The IPMC membrane corroborates a huge bending deformation with more than 90<sup>0</sup> angle curvature bending at 3 V applied. For the Ag nanopowder casting, the in-between adhesion of the electrode of metal and the polymer matrix membrane delineates superior attributes; however, this will enhance the surface resistance up to 2 Ω/square. To solve these difficulties, a non-toxic electroless plating of silver is introduced to diminish the resistance of the surface. Moreover, the resistance of the surface is lessened to 0.12–0.15 Ω/square after this electroless plating method. Furthermore, in the procedure, the contact pad will incline to form Ag2O for the oxidation of Ag by the influence of OH� from the water that will increment more the resistance of the

surface. The nickel electroforming in the contact pad will lessen the surface's resistance because it will preclude the Ag2O formation. This novel is emerging procedure has the eminence of the better bond between the polymer membrane and electrode, shorter process time, substantial driving force in the lower driving voltage (around 0.22gf at 3 V), low cost those making it potential for application of mems based device (**Figure 2**).
