International Journal of Instrumentation Science

p-ISSN: 2324-9994    e-ISSN: 2324-9986

2016;  5(1): 15-18



Design of Polydimethylsiloxane/Nylon 6/Nanodiamond for Sensor Application

Ayesha Kausar

Nanoscience and Technology Department, National Centre For Physics, Quaid-i-Azam University Campus, Islamabad, Pakistan

Correspondence to: Ayesha Kausar, Nanoscience and Technology Department, National Centre For Physics, Quaid-i-Azam University Campus, Islamabad, Pakistan.


Copyright © 2016 Scientific & Academic Publishing. All Rights Reserved.

This work is licensed under the Creative Commons Attribution International License (CC BY).


In this attempt, polydimethylsiloxane (PDMS) and nylon 6 (Ny 6) were blended as matrix, while nanodiamond (ND) was used as nanofiller for nanocomposite formation. 2,2-Diethoxyacetophenone was used as photo-initiator. Various nanodiamond contents were loaded in PDMS/Ny 6/ND nanocomposite to form the matrix solution. The films were formed on the silicon wafers using dip coating technique. The materials were analyzed for thickness tests, adhesion tests as well as shear modulus G' studies vs. temperature and frequency. Thicknesses 30-45 μm was obtained by applying several layers of nanocomposite on the top of each other for various time spans. Shear modulus was found to be independent of the applied frequency, which was typical for rubber elastic material. However, the shear modulus was found to increase slightly with temperature. Adhesion between nanodiamond and PDMS/Ny 6 matrix was found to be strong because of covalent bonding. Manual peeling of the nanocomposite was not achieved owing to strong adhesion. The novel materials may find potential application in tactile sensors and sensor packaging.

Keywords: Polydimethylsiloxane, Nylon 6, Nanodiamond, Adhesion, Shear modulus, Sensor

Cite this paper: Ayesha Kausar, Design of Polydimethylsiloxane/Nylon 6/Nanodiamond for Sensor Application, International Journal of Instrumentation Science, Vol. 5 No. 1, 2016, pp. 15-18. doi: 10.5923/j.instrument.20160501.03.

1. Introduction

For modification of polymeric materials pro sensor applications in chemical and biomedical fields, a great deal of research and development effort has been made [1, 2]. By interaction with diverse chemicals, the modulation of material conductivity has been carried out. For detection of organic and inorganic liquid or gases (hydrocarbon, gasoline, ammonia, nitrogen dioxide), sensors have been primarily applied [3, 4]. Generally, suitable sensors are preferred to meet the following features: (i) sensing constituent with high detection rate (ii) reproducible and reversible responses (iii) respond to a wide range of chemicals and concentrations; (iv) easy fabrication with compact, simple and economical design (v) corrosion and weathering resistant [5]. Polydimethylsiloxane (PDMS) is a commercially existing clean room attuned type silicone rubber with extensive range of applications. Generally, it is utilized as mechanical interconnection layer between two silicon wafers (ion selective membranes) and as spring material in accelerometers [6, 7]. Other perspective applications are as top layer elastomers on tactile sensors without effecting device sensitivity. Moreover, they may act as encapsulation material in order to decouple sensors electrically and mechanically from their environment [8, 9]. Because of its low curing temperature, it is also useful in integrated electronics and sensors. In comparison to other polymers, PDMS have [10], low glass transition temperature ~125 °C, shear modulus between 100 kPa and 3 MPa, and low loss tangent tan δ ~0:001. Furthermore, they also have small temperature changes for thermal expansibility α ~20×10-5 K-1 [11, 12], excellent dielectric strength ~ 14 V μm-1, outstanding gas permeability, high compressibility, and usability over a wide temperature range (from -100°C to +100°C) [13]. Although, PDMS have essentially nontoxic nature and have low chemical reactivity (except at extremes of pH). Nylon-6 is a biodegradable and biocompatible polymer. It is extensively used in numerous industrial fields due to its low cost, superior ability of fiber formation, good mechanical strength, and strong chemical and thermal stabilities [14, 15]. Furthermore, electrospun nylon-6 mats have enhanced hydrophilicity and may be a prospective candidate for this application. This polymer is well-recognized with nanoparticles due to its advantages such as hydrophobic features, good stability, UV blocking ability, and excellent photocatalytic and antimicrobacterial capacity [16]. Nanodiamond is well suited due to its outstanding features for numerous applications comprising thermal conducting and heat interface, electronic and optic mechanics, composite electroplating and electroless plating, lubricating oil, and biomedical technology. The high mechanical, optical properties, high surface area, tunable structure, outstanding wear ability, and friction of nanodiamond make them active filler for polymer nanocomposite [17-21]. Nanodiamond films have been deposited by hot filament chemical vapor deposition (HFCVD) method and techniques such as scanning electron microscopy (SEM), Raman spectroscopy and X-Ray diffraction (XRD). The studies have shown effect of carbon concentration on microstructure of nanodiamond films [22-25]. This paper describes the formation and processing of polydimethylsiloxane, nylon 6, and nanodiamond nanocomposite. Various weight content of nanodiamond was loaded in the samples. 2,2-Diethoxyacetophenone was used as photoinitiator. The resulting films were dip coated on the silicon wafers. The layer thickness versus spin rate, and variation of shear modulus G with shear rate were measured and discussed.

2. Experimental

2.1. Materials

Polydimethylsiloxane, 2,2-diethoxyacetophenone (Photoinitiator, DEAP), and diamond nanopowder were obtained from Aldrich.

2.2. Characterization Techniques

Thickness of the prepared films was measured with DEKTAK II surface profiler with needle radius 250 μm and stylus force 0.1 mN. The variation in shear modulus G' due to changes in other parameters can be measured with Bohlin rheometer system with frequencies in the range of 0.005 and 30 Hz and temperature between 0° and 80°C.

2.3. Preparation of Polydimethylsiloxane/Nylon 6/Nanodiamond (PDMS/Ny 6/ND) Composite

To 1 mL of xylene, 50 wt.% of PDMS and 1 wt.% DEAP was added and the solution was sonicated for 6 h at 60°C. 1 wt. % nylon 6 and 1-10 wt.% nanodiamond was dispersed separately in 1 mL of xylene with sonication of 3 h. Later, both the solutions were mixed and centrifuged for 2h at 2000 rpm. The mixture was kept over night for 24 h. The mixture was then coated on silicon wafers using dip casting technique for 1 min. The wafer was rinsed with deionized water and dried at 60°C for 1 h [26].

3. Results and Discussion

3.1. Thickness Study

The thickness of PDMS/Ny 6/ND film was measured as mentioned in Section 2.2. The measurement results are shown in Fig. 1. Thicknesses about 30-45 μm was obtained by applying several layers of nanocomposite on the top of each other. The results have shown that the thickness of both PDMS/Ny 6/ND 5 (5 wt.% nanodiamond) and PDMS/Ny 6/ND 10 (10 wt.% nanodiamond) nanocomposite was found to increase with the dipping time. The maximum results were obtained for the PDMS/Ny 6/ND 10 nanocomposite having increased nanodiamond content.
Figure 1. Thickness at different coating time (A) PDMS/Ny 6/ND 5 and (B) PDMS/Ny 6/ND 10

3.2. Shear Modulus Versus Frequency

The shear elastic modulus G can be divided into real and imaginary part [27]. The variation in shear modulus G' due to changes in frequency was measured with Bohlin rheometer system. The shear modulus G' versus applied frequency is shown in Fig. 2. Generally, shear modulus is independent of the applied frequency, which is typical for a rubber elastic material. The results reinforce the applicability of the material for sensor application.
Figure 2. Shear modulus G' versus shear rate

3.3. Shear Modulus Versus Temperature

The shear modulus was seemed to be independent of the applied temperature, as shown in Fig. 3. The figure shows that the shear modulus increased with the temperature, which is typical for rubber elastic materials [28]. However, the change in shear modulus G' was so small that the value could not be determined with precision. The results indicated that the change in shear modulus G' was almost steady for the analyzed samples.
Figure 3. Shear modulus G' versus temperature

3.4. Adhesion of PDMS/Ny 6/ND Nanocomposite

Nanodiamond acted as coupling agent between the PDMS/Ny 6 polymers and the silicon substrate. The nanocomposite was capable of chemical interaction with the silicon oxide surface. In this way, nanodiamond acted as a linker to bind the silicon oxide surface to PDMS/Ny 6 matrix covalently [29]. The adhesion between the nanocomposite and substrate was very strong. Manual peel test was applied to separate the nanocomposite from the wafer; the material was not found to separate from the wafers. The results depicted strapping linkage between the filler and matrices due to effective interfacial contact.

4. Conclusions

According to the results, PDMS/Ny 6/ND nanocomposite showed rubber elastic behavior. The shear modulus was found to be independent of the applied frequency. However, it showed small change with temperature. Because of the nanodiamond as PDMS/Ny 6/ND component, it showed fine adhesion to the silicon substrate. Results have suggested that the novel PDMS/Ny 6/ND nanocomposite materials have shown several potential applications in tangible sensors and also in packaging for sensor.


[1]  Kausar, A., 2016. “Thermal Conductivity Measurement of Polyvinylpyrrolidone/ Polyethylene/ Graphene Nanocomposite.” Nanoscience and Nanotechnology, 6(2): 34-37.
[2]  Grigor, J.M., Theaker, B.J., Alasalvar, C., O’Hare, W.T. and Ali, Z., 2002. “Analysis of seafood aroma/odour by electronic nose technology and direct analysis. In Seafoods — Quality, Technology and Nutraceutical Applications”. Springer Berlin Heidelberg. pp. 105-121.
[3]  Kausar, A., 2016. "Thermal and Rheological Properties of Waterborne Polyurethane/Nanodiamond Composite." Nanoscience and Nanotechnology 6(1): 6-10.
[4]  Meer, S., Kausar, A. and Iqbal, T., 2016. “Trends in Conducting Polymer and Hybrids of Conducting Polymer/Carbon Nanotube: A Review.” Polymer-Plastics Technology and Engineering, Doi:1080/03602559.2016. 1163601.
[5]  Arquint, P., van der Wal, P. D., van der Schoot, B. H. and de Rooij N F. 1995. Flexible polysiloxane interconnection between two substrates for microsystem assembly. Proc. Transducers. 95: 263-266.
[6]  Antonisse, M. M., Engbersen, J. F. and Reinhoudt, D. N. 1995.” Nitrate and bicarbonate selective CHEMFETs”. 867-869.
[7]  Lötters, J. C., Olthuis, W., Veltink, P. H. and Bergveld, P. 1996. “Polydimethylsiloxane as an elastic material applied in a capacitive accelerometer”. Journal of micromechanics and microengineering. 6(1): 52.
[8]  Chu, Z. 1996. Flexible package for a tactile sensor array. In Proc. 1996 National Sensor Conf. (Delft, The Netherlands). March 20–21: pp. 121-124.
[9]  Anh, D.T., Olthuis, W. and Bergveld, P., 2001. “Electrochemical characterization of Prussian Blue by using the EMOSFET”. Sensors and Actuators B: Chemical, 78(1): 310-314.
[10]  Zuber, M., Zia, K.M., Tabassum, S., Jamil, T., Barkaat-ul-Hasin, S. and Khosa, M.K. 2011. “Preparation of rich handles soft cellulosic fabric using amino silicone based softener, part II: Colorfastness properties”. International journal of biological macromolecules, 49(1): 1-6.
[11]  Lötters, J.C., Olthuis, W., Veltink, P.H. and Bergveld, P. 1997. “The mechanical properties of the rubber elastic polymer polydimethylsiloxane for sensor applications”. Journal of Micromechanics and Microengineering, 7(3): 145.
[12]  Van Krevelen, D. W., & Hoftyzer, P. J. 1976. “Permeation of polymers: the diffusive transport of gases, vapours and liquid in polymers”. Properties of Polymers, Elsevier, Amsterdam. 403-425.
[13]  Pey, J. L. 1997. “Corrosion protection of pipes, fittings and component pieces of water treatment and pumping stations”. Anti-Corrosion Methods and Materials. 44(2): 94-99.
[14]  Kausar, A., 2016. “Rheology and Mechanical Studies on Polystyrene/Polyethylene-graft-maleic Anhydride Blend and Cellulose-Clay Based Hybrid”. International Journal of Composite Materials, 6(3): 63-67.
[15]  Linsebigler, A. L., Lu, G. and Yates Jr, J. T. 1995. Photo catalysis on TiO2 surfaces: principles, mechanisms, and selected results. Chemical reviews. 95(3): 735-758.
[16]  Hoffmann, M. R., Martin, S. T., Choi, W. and Bahnemann, D. W. 1995. Environmental applications of semiconductor photocatalysis. Chemical reviews. 95(1): 69-96.
[17]  Ashraf, R., Kausar, A. and Siddiq, M. 2014. “High-performance polymer/nanodiamond composites: synthesis and properties”. Iranian Polymer Journal. 23(7): 531-545.
[18]  Shah, R., Kausar, A., Muhammad, B. and Shah, S. 2015. “Progression from graphene and graphene oxide to high performance polymer-based nanocomposite: A review”. Polymer-Plastics Technology and Engineering, 54(2): 173-183.
[19]  Jabeen, S., Kausar, A., Muhammad, B., Gul, S. and Farooq, M. 2015. “A review on polymeric nanocomposites of nanodiamond, carbon nanotube, and nanobifiller: Structure, preparation and properties”. Polymer-Plastics Technology and Engineering. 54(13): 1379-1409.
[20]  Kausar, A. 2015. “Nanodiamond/mwcnt-based polymeric nanofiber reinforced poly (bisphenol a-co-epichlorohydrin)”. Malaysian Polymer Journal. 10(1):.23-32.
[21]  Ashraf, R., Kausar, A. and Siddiq, M. 2014. “Preparation and properties of multilayered polymer/nanodiamond composites via an in situ technique”. Journal of Polymer Engineering, 34(5): 415-429.
[22]  Kausar, A. 2016. “Bucky Papers of Poly (methyl methacrylate-co-methacrylic acid)/Polyamide 6 and Graphene Oxide-Montmorillonite”. Journal of Dispersion Science and Technology. 37(1): 66-72.
[23]  Kausar, A., Zulfiqar, S., Ahmad, Z. and Sarwar, M.I. 2010. “Facile synthesis and properties of a new generation of soluble and thermally stable polyimides”. Polymer Degradation and Stability, 95(12): 2603-2610.
[24]  Rafique, I., Kausar, A., Anwar, Z. and Muhammad, B. 2016. “Exploration of Epoxy Resins, Hardening Systems, and Epoxy/Carbon Nanotube Composite Designed for High Performance Materials: A Review”. Polymer-Plastics Technology and Engineering, 55(3): 312-333.
[25]  Kausar, A., Ashraf, R. and Siddiq, M. 2014. “Polymer/nanodiamond composites in Li-ion batteries: A review”. Polymer-Plastics Technology and Engineering, 53(6): 550-563.
[26]  Kanamori, Y., Roy, E. and Chen, Y. 2005. “Antireflection sub-wavelength gratings fabricated by spin-coating replication”. Microelectronic Engineering. 78: 287-293.
[27]  Jansen, J.A. 2001. “Failure analysis of a polysulfone flow sensor body—A case study”. Practical Failure Analysis, 1(2): 55-58.
[28]  Richaud, E., Colin, X., Monchy‐Leroy, C., Audouin, L. and Verdu, J. 2011. “Diffusion-controlled radiochemical oxidation of bisphenol A polysulfone”. Polymer International, 60(3): 371-381.
[29]  Thominette, F., Metzger, G., Dalle, B. and Verdu, J. 1991. “Radiochemical ageing of poly (vinyl chloride) plasticized by didecylphthalate”. European polymer journal. 27(1):.55-59.