We use dissipative particle dynamics to simulate the controlled transport of flexible polymers through coated slit and cylindrical pores. Pores are coated inside with solvent-sensitive polymer brushes. Stretch-to-collapse transition then controls the permeability of the coated pores. We change the solvent quality with respect to the polymer brushes and study the flow of flexible polymers through the pores. We show that stretched brush chains close the pores and compress the polymers in the centre of the pores. The collapsed brush chains relieve compression and rapid change in permeability is observed. In open pore state, polymers partially accommodate on the brush layer and partially migrate towards the center of the pores, where the flux is maximal. Finally, we observe that polymers tend to align in the direction of the flow.