Response Characteristics of Thermoresponsive Polymers Using Nanomechanical Cantilever Sensors

摘要

We investigated coatings of thermally responsive thin polymer films prepared on nano-mechanical cantilever sensor (NCS): (i) a PNIPAM brush, and (ii) an interlinked ppDEA polymer. Upon heating from 22 to 50 degrees C in water, a minimum in the differential deflection between 31.9 +/- 1.7 degrees C (PNIPAM) and 47.7 +/- 1.9 degrees C (ppDEA) was measured. The minimum in differential deflection can be associated with the lower critical solution temperature (LCST) of the films. Below the LCST the NCS deflection corresponds to a bending toward the thermally responsive polymer film side, associated to dehydration. At higher temperature, the deflection was reversed, i.e., away from the polymer coating. This response is mainly attributed to a bimaterial effect between the collapsed polymer and the NCS material. The LCST of the PNIPAM brush layer and the ppDEA film were close to that reported for the bulk polymers.