Fiber optic sensors offer the ability to measure different types of physical quantities in more harsh environments, such as temperature, pressure and deformations. Some of these demanding environments include chemicals that affect the sensitivity of the sensor, and therefore its resili-ence deteriorates. This work focuses on using experimental techniques to find a method that protects the optical fiber in these chemically demand-ing environments, by coating the fiber with a polymer layer which has the task of protecting it in such environments. A challenge that comes with coating the fiber optic sensor with a polymer layer is that the ability to obtain information becomes more difficult as, its sensitivity deterio-rates. In this project, a type of polymer called polyimide will be tested, using different concentrations and number of layers coated on the optical sensor to investigate the extent that these factors affect the sensor´s ability to cope in chemically demanding environments and also how the sensi-tivity is affected. Thus, the coating method used was soap film coating (SFC). A spectrometer was used to examine the sensitivity of the sensor (using total internal reflection (TIR) and surface plasmon resonance (SPR)). The examination of the resistance of the optical fiber was meas-ured by immersing the polymer-coated sensor in a corrosive liquid for various time intervals and then examining its protective ability. The re-sults obtained through this work demonstrate that polyimide as a coating material provides a protective effect by improving the resistance. The sen-sitivity was most affected when the concentration of the polyimide layer increased from 1-layer to 2-layer polyimide at high concentrations. Re-sistance also increased as the concentration increased, however, 1-layer and 2-layer protection did not have a major impact. The results of this project can be used to further test different types of polymers, for example PVDF. Even more tests with the same attitude and conditions should be carried out to ensure the conclusions and results, and to estimate the measurement uncertainties in the work.