Evaluation of Surface-initiated Polymer brush as Anti-scaling Coating for Plate Heat Exchangers

Jakob Ege Friis, Guruprakash Subbiahdoss, Gorm Gerved, Allan Hjarbæk Holm, Olga Santos, Anders Bank Blichfeld, Saeed Zajforoushan Moghaddam, Esben Thormann, Kim Daasbjerg, Joseph Iruthayaraj, Rikke Louise Meyer


Inorganic fouling is one of the challenging problems in heat exchanger applications. One approach to mitigate fouling is to employ surface coatings. In this study, we evaluated the feasibility of surface-initiated polymerization (SIP) as thin coating technology to mitigate CaCO3 formation for heat transfer applications. The extent of formation of CaCO3 on different types of poly(oligoethyleneglycol) methacrylate brushes (POEGMA) was investigated under stagnant and flow heat-exchanging conditions. Polymer brushes of high graft density reduced the surface coverage of CaCO3more effectively than the low graft density brushes. By contrast, the thickness of the brush did not correlate with the surface coverage of CaCO3. The comparison of stagnant and flow experiments revealed that the antiscaling property of- POEGMA brushes was due to low adhesion CaCO3 deposits though the brushes themselves do not prevent the nucleation of CaCO3. b. Finally, the SIP process was successfully scaled-up to coat commercial heat exchanger plates with thickness and homogeneity comparable to lab-scale surfaces. Under industrial testing, the POEGMA brushes extended the performance by 50 h before the commencement of complete blockage.