Plasma reactor operating at low pressures (0.2-1 Torr) at 13.56 MHz has been developed with an idea to optimize the treatment of polymers, biological and textile materials. The reactor proved very effective in treatment of polymer surfaces and wool fabrics in order to improve wettability, efficiency of dyeing and printing as well as to reduce the felting shrinkage. It also gave good results in improving germination of seeds. The basic conditions that the reactor has to satisfy are: the energy of ions that hit the surface has to be low and the reactor should be efficient in production of active radicals. Two systems with different geometries were studied, both capacitively coupled plasma reactors operating at 13.56 MHz. Cylindrical geometry was selected in order to minimize the energy of ions reaching the surface. Modeling of the discharge was performed with an aim to verify the energy distribution function of ions. As a critical diagnostic test of the system, voltage and current probes were developed to check the operation mode of the discharge. Oxygen, air and argon were used with different results.