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Response Characteristics of Thermoresponsive Polymers Using Nanomechanical Cantilever Sensors
Author(s) -
Bradley Calvin,
Jalili Nader,
Nett Sebastian K.,
Chu Liqiang,
Förch Renate,
Gutmann Jochen S.,
Berger Rüdiger
Publication year - 2009
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200900081
Subject(s) - lower critical solution temperature , polymer , materials science , cantilever , deflection (physics) , polymer chemistry , brush , polymer brush , composite material , coating , thin film , chemical engineering , nanotechnology , optics , copolymer , polymerization , physics , engineering
We investigated coatings of thermally responsive thin polymer films prepared on nanomechanical cantilever sensor (NCS): (i) a PNIPAM brush, and (ii) an interlinked ppDEA polymer. Upon heating from 22 to 50 °C in water, a minimum in the differential deflection between 31.9 ± 1.7 °C (PNIPAM) and 47.7 ± 1.9 °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.