The polymer was prepared by refluxing PHMS, fullerene and benzoyl peroxide (BPO) via in situ polymerization at 70˚C for 2.5 hours in the water bath. Precipitation was done by methanol and dried.

IPN was synthesized via in situ polymerization by systematic variations of concentration benzoyl Peroxide (BPO), fullerene, acrylonitrile and divinyl benzene (DVB) as a cross-linker. The systems were kept over water bath for 2.5 hours at 70˚C under an inert atmosphere of nitrogen. These polymer networks were precipitated and dried [23] - [28] . Our experimental results revealed the significant impact of interfacial tension of both droplets and the surrounding medium on the overall wettability of the solid-medium-droplet system. The predicted results were within ± 25% deviation from that of the experimental observation for most of the cases. In contrast, the application of the previously reported theories resulted in a larger deviation (above ± 35%) for all samples.

Cross-linked density of polymer network was calculated by measurements of solvent absorbency. The swelling data was calculated by soaking sample in different polar and nonpolar solvents such as dimethyl formamide (DMF), dimethyl sulphoxide (DMSO), dioxane, benzene or toluene until an equilibrium weight was achieved (~24 hrs.). Weight measurements were carried out by blotting the samples and immediately weighing them. The percentage swelling was calculated according to the following relationship as shown in Table 1.

% Swelling = ( W s − W d W d ) × 100

where, W_s = weight of swollen IPN and W_d = Weight of dry IPN.

The structural analysis of IPN was studied by IR spectroscopic technique using Vertex 70 (Bruker) instrument with KBr pellet, data acquisition was based on two channel delta-sigma ADCs.

DSC was carried on a V2.2 Dupont calorimeter, equipped with data station. Sample prepared by casting sample IPN into aluminum pans from 5% solution in chloroform. The specimen was subjected to further drying under vacuum at room temperature for one day. The sample size was 15 mg. Experiments were carried out at a heating rate of 10˚C/min under nitrogen atmosphere.

The polymer network was analyzed using TESCAN MIRA-3 FESEM, at 10 Kv and under 2500× magnification.

The fluorescent emission spectra of polymeric network were recorded on a spectrofluorometer (Fluorolog 3, Model FL 3-22), for fluorescence properties.

Contact angle measurement for hydrophobic or hydrophilic characterization of the synthesized IPN was carried out with the Dataphysics Instrument mode TBU-100 with distilled water as a droplet at 300C room temperature.

The detailed vibrational analysis of the synthesized IPN was performed by us, which reveals shifting in band positions of the reacting molecular structures. IR study for pure fullerene shows peaks at 1430 cm⁻¹, 527 cm⁻¹ (for C-C vibration mode) and 1600 cm⁻¹ (for −C=C− mode) respectively. For pure PAN it shows peak at 2944 cm⁻¹ (Aliphatic CH vibrations), 1380 cm⁻¹ (Aliphatic CH3), 1450 cm⁻¹ (CH₂ Vibrations) and 2224 cm⁻¹ (CN) and for pure PMHS it shows the peak at 1050 cm⁻¹ (Si-O), 1250 cm⁻¹ (Si-C), 2225 cm⁻¹ (Si-H) and 3000 cm⁻¹ (C-H) respectively. While Figure 1 shows IR spectra for the synthesized polymer network, which reveals the presence of fullerene at 500 cm⁻¹ (for caged vibrations), 1632 cm⁻¹ (for C=C mode), for polyacrylonitrile it shows peak at 3077 cm⁻¹ (Aliphatic CH vibrations), 1299 cm⁻¹ (Aliphatic CH₃), 1408 cm⁻¹ (CH₂ Vibrations) and 2083 cm⁻¹ (CN) and for PMHS it shows the peak at 1069 cm⁻¹ (Si-O), 1262 cm⁻¹ (Si-C), 2168 cm⁻¹ (Si-H) and 2966 cm⁻¹ (C-H) respectively. Thus, as evident from IR analysis that shifting in band positions has taken place, which was an indication of proper interpenetration among the reacting species [10] [11] . The FTIR investigations revealed multiple non-covalent interactions achieved by polymerization with physical anchoring on the polymeric network surfaces. Such interactions can be recognized as the driving force for the fabrication of hydrophobic flexible silicon-based materials with a self-cleansing action. This seems to be very interesting and vowing for the hydrophobic property of PMHS, which can do better intermingling with the swelling behavior of the IPN. It was observed that the fabricated IPN system completely protect the desired material from water and more or less the percolated water if enter the IPN surface, get entangled inside it in the form of hydrogel and lock the movement of water molecule completely at that position.

It is evident from Figure 2 (DSC endotherm curve) that the synthesized polymeric network exhibits an endotherm peak approximately at 117˚C, which corresponds

to the crystallization peak (T_c) of the polymeric network. Such a peak indicates the crystalline nature of IPN. T_g value for pure polyacrylonitrile was found to be at 120˚C. The synthesized IPN does not show any T_g peak. The absence of T_g peak and clear observable T_c peak indicates crystalline behavior of IPN [20] [21] [22] . This might have been a result of proper packing and interpenetration of fullerene spheres differently at different regions with the reacting species.

The structure of the fabricated fullerene-based interpenetrating polymer network of PMHS and PAN was detected by means of SEM technique which confides dual phase morphology and transparent nature (Figure 3). The network structure was variegated, which indicates sample heterogeneity of solution, used for the film preparation, which describes the happening of phase separation just after solvent evaporation. This was clearly prominent in the microscopic picture. The surface of IPN composed of fullerene, PMHS and PAN was not smooth. Some projections of different sizes were observable. This indicated that under the top layer, there was a heterogeneous region, depicting clear dual-phase morphology. Thus, the detailed morphological study of the IPN reveals a dual-phase morphology and transparent character.

Figure 4 reveals fluorescent excitation and emission spectra of IPN 5. The fluorescent excitation and emission spectra of IPN Nano sheets depict that the polymeric network exhibits analogous excitation (A) and emission spectra (B). The emission spectra reveal a broad peak centered at about 400 nm, owing to n ® π* electronic transitions found in polymeric networks. Emission spectra generated by radiative decay of excitations exhibit a maximal peak at 450 nm, suggesting that the synthesized IPN Nano sheets were typically high-intensity blue light emitting materials.

To establish the hydrophobic or hydrophilic nature of synthesized IPN, hydrophobic characterization using contact angle—a measurement through the liquid when the liquid interface meets a solid surface. The contact angle for hydrophilic (love water) is 0˚ < θ < 90˚, hydrophobic (scared of water) is 90˚ < θ < 150˚ and superhydrophobic is θ > 150˚ [14] [29] . High contact angle shows low wettability and vice versa, was carried out with the Dataphysics Instrument mode TBU-100, 3.34 µL distilled water droplet was used on the sample at 30˚C room temperature, it was observed from the result, Figure 5 that left contact angle of synthesized IPN was 103.8⁰ and right contact angle was 104.1⁰ which was greater

than 900 and confirm the hydrophobic nature of synthesized IPN for hydrophilic contact angle should be less than 90⁰.

The solute component of IPN was removed with the help of the Soxhlet apparatus. The percentage of extractable material was calculated (Table 1) using the following equation.

% Extractablematerial = ( W b − W a W a ) × 100 (1)

where,

W_b = Weight of IPN before extraction and

W_a = Weight of IPN after extraction.

The swelling was calculated in DMF, DMSO, benzene and toluene till a constant mass was achieved (nearly 24 hrs.) (Table 1). The percentage swelling (Tables 1-5 was calculated according to the following relationship.

% Swelling = ( W s − W d W d ) × 100 (2)

where,

W_s = weight of swollen IPN and

W_d = Weight of dry IPN.

IPN sample was taken and its crosslink density was determined (Tables 2-5) by using the swelling data of IPN in DMF by using the Flory-Rehner equation.

1 M c = − ln ( 1 − V p ) + V p + X 12 V p 2 p V 1 ( V p 1 / 3 − V p / 2 ) (3)

where, M_c = average molecular weight of network between crosslinks, p = density of the network, V₁ = molar volume of solvent, and V_p = volume fraction of polymer in swollen gel, X₁₂ = polymer solvent interaction parameter, calculated by the expression.

X 12 = B + V 1 ( δ p − δ s ) 2 R T (4)

where δ_p and δ_s = solubility parameters of polymer and swelling solvent, respectively, and B = lattice constant, which was taken as 0.34.

For swelling measurement and crosslink density calculation of IPN seems to be very interesting and vowing for the hydrophobic property of PMHS, which can do better intermingling with the swelling behavior of the IPN. It was clear that the fabricated IPN system completely protects the material from water, more or less if water percolates it enter into the IPN surface, get entangled inside in the form of hydrogel and locks further movement of water molecule completely at that position.