Analysis of responsive polymer films using surface acoustic waves.

The Surface Acoustic Wave (SAW) technique is applied for the first time to quantify the properties of a responsive polymer brush layer. Using a single SAW chip, the response of five different brush compositions to several pH changes was monitored in parallel in a single run. These results were compared with QCM-D studies on the same system. SAW exhibited two remarkable advantages against QCM-D: (i) multiplexing capability, which allowed considerable reduction in experimental time and expenses (1/8 reduction of experimental time, 1/5 in the number of chips, and 1/10 in solvent consumption in our case), and (ii) higher sensitivity in both mass and viscosity change than QCM-D (4-5 times higher in our systems). Our results demonstrate the suitability and advantages of the SAW technology for application in polymer science, in particular for the study of the compositional effects in responsive thin layers.