the results analysis can be summarized in several points as shown below: 1. The surface roughness and the pore diameter of PS were increased with the change of the HFc 10, 20, and 30 %. 2. Thin layers of graphene on the surface of PS have a main role for increasing the surface area for PS sample. That improved the performance of PS samples as gas sensors. 3. The responses and sensitivity have been improved when deposited graphene layer on PS rather than PS samples and further enhancement after doping the TiO2 film with graphene. 4. The best result was at G – TiO2 /PS sample as gas sensor, then G/PS sample and the least quality was at PS samples. 5. The surface roughness and PS diameter change with the change of HFc. 6. G-TiO2 was prepared using sol gel. 7. Coating the PS surface with graphene leads to a change in the surface shape and PS pour diameter. 8. The addition of TiO2 with graphene affects the surface roughness and shape. 9. The surface of the PS remains crystalline after its transformation into a nana-form. 10. Adding graphene to the surface of PS leads to an increase in the surface sensitivity of H2S gas. 11. Response time and recover time has been changed significantly with the addition of graphene to the surface. 12. The surface sensitivity is highest when TiO2 and graphene were present on the surface. 13. The response time and recovery time values changed significantly for the G-TiO2/PS samples. 14. In this work, the best sensitivity to H2S gas was at HFc = 10% and temperature 27 C°. 5.2 Future Work Further research may be done based on the findings of this study, which includes the following: 1- Studying the same samples for the other types of sensor. 2- Preparing TiO2 NPs using different methods like hydrothermal and laser ablation technique for depositing on PS surface and study the effect on sensitivity for organic vapors 4- Replacing the graphene with MWCNTs and applying it with the same sensor 5- Studying optoelectronic applications such as solar cell and photo detector for PS, G/PS and G-TiO2/PS samples that prepared in this work. 6- Applied the samples as bio sensor such as anti-bacterial. 7- Preparation of PS samples using a change in etching time . 8- Examination of samples as a gas sensor using Photoluminescence (PL). 9- Preparing more than one nana-metal and depositing it on the surface of the PS and applied a gas sensitivity test. 10- Conducting the same preparation of samples and depositing them on the ITO class and making a comparison with the results we obtained. 11- Study the properties of photo voltaic of samples. 12- Synthesis of nana-carbon dot and replacement with graphene, study of its properties and application as a sensor.
