Patterned and switchable surfaces for biomaterial applications

Chapter 5 – Surface plasmon resonance imaging of polymer microarraysUpon the cooling of the microarray below the LCST, a gradual decrease in theintensity of the reflected light was observed as the polymer spots swell and take onmore water (Figure 5.3), whereupon exothermic enthalpy is the thermodynamicdriving force for hydrogen bond formation between water molecules and thepolymer’s polar groups. This continued until the SPR signal intensity declined to thebaseline level. Therefore, the change in PNIPAAm morphology was reversible andcould be repeated over three heating and cooling cycles in succession (Figure 5.3).Similar results for PNIPAAm coatings have been observed previously by SPR [276-278].5-172