Linear thermoresponsive acrylamid based microgels adsorbed on a surface
Résumé
A gel is a dispersed system which consists of at least two different components: a solid or flexible mesh and a fluid. If the fluid is water the gel is called a hydrogel. Microgels are gels smaller than 10 μm and can be used in a wide range of applications like drug delivery and smart surface coatings. If the microgel consists of acrylamides like N-isopropylmethacrylamide (NIPMAM) or N-n-propylacrylamid (NNPAM) as network component, they show a volume phase transition (VPT) at a certain temperature, the volume phase transition temperature (VPTT). An increase in temperature above the VPTT leads to an abrupt decrease in size and a decrease in temperature leads to an abrupt increase in size. The VPTT is specific for each monomer. To use microgels in sensors or for nanoactuators the thermoresponse has to be precise and well known. That is why we investigated microgels with a complex architecture containing NIPMAM and NNPAM. These particles show a tunable linear change in size between the two VPTTs of NNPAM (22 °C) and NIPMAM (43 °C). Furthermore, we deposited these microgels on surfaces and investigated the properties of the microgel coating. The properties of these particles (like phase transition behavior or particle size) can be adjusted by selecting specific synthesis conditions.