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Thermosensitive copolymer coatings with enhanced wettability switching
Mahaveer D Kurkuri1, Matthew R Nussio, Alec Deslandes
1School of Chemistry, Physics and Earth Sciences, Flinders University, Bedford Park, South Australia 5042, Australia.
Langmuir : the ACS Journal of Surfaces and Colloids
|March 18, 2008
Summary
Researchers developed switchable polymer coatings for silicon surfaces. These poly(N-isopropylacrylamide) and poly(acrylic acid) copolymers offer tunable hydrophilic and hydrophobic states for advanced biointerface applications.
Area of Science:
- Materials Science
- Polymer Chemistry
- Surface Science
Background:
- Surface-grafted polymer networks offer tunable properties for biointerfaces.
- Poly(N-isopropylacrylamide) (PNiPAAm) and poly(acrylic acid) (PAAc) are stimuli-responsive polymers.
- Controlling polymer conformation is key to tuning surface properties.
Purpose of the Study:
- To investigate the influence of an expanded polymer conformation on the switchability of PNiPAAm-PAAc copolymers.
- To optimize monomer ratios for maximum temperature-induced wettability changes.
- To explore the potential of these coatings for controlling protein attachment.
Main Methods:
- Surface-grafted polymerization of PNiPAAm-PAAc copolymers on silicon.
- Characterization using XPS, ellipsometry, and diffuse reflectance IR.
- Determination of LCSTs and wettability via spectrophotometry and contact angle measurements.
- AFM for surface topography analysis.
- Fluorescence microscopy and spectroscopy for protein attachment studies.
Main Results:
- Copolymer conformation was influenced by pH-induced electrostatic repulsion.
- Maximum switching in contact angle was observed at a 36:1 PNiPAAm to PAAc ratio.
- Reversible protein attachment was demonstrated as a function of temperature.
- Surface topography varied with temperature.
Conclusions:
- Expanded PNiPAAm-PAAc copolymers exhibit tunable switchability between hydrophilic and hydrophobic states.
- Optimized copolymer ratios enhance temperature-induced wettability changes.
- These switchable biointerfaces show promise for applications in biomaterials, biochips, drug delivery, and microfluidics.
