IPC RWTHAK RichteringResearchCurrent Projects > Polyelectrolyte multilayers on soft and porous substrates
Sunday, 20.04.2014

Polyelectrolyte multilayers on soft and porous substrates (DFG project)

In this project we investigate the layer-by-layer assembly of polyelectrolyte multilayers on unconventional soft and porous supports as provided by microgels. Microgels, such as Poly(N-isopropylacrylamide) (PNIPAM) are thermosensitive materials and undergo a volume phase transition temperature at 32°C. This makes them potential candidates for use in drug encapsulation, transport, and controlled release in the body. We synthesise different core-shell systems based on PNIPAM to constitute building blocks of various mesh size. The challenge is to use layer-by-layer deposition of polyelectrolyte multilayers on a substrate of changing size with temperature, whereby the polyelectrolytes can also penetrate the soft and porous substrate to confer novel properties via surface modification. We shall investigate parameters influencing the formation and growth behaviour (molecular weight, charge density, salt, ionic strength, pH, temperature) and characterise both the substrates and the multilayers using various techniques. The project aims at a better understanding of the interactions and the physico-chemical aspects coming into play not only within the multilayers as build on soft and porous substrates but also between the layer and the thermosensitive substrate.


Polyelectrolyte microgels based on poly-N-isopropylacrylamide: influence of charge density on microgel properties, binding of poly-diallyldimethylammonium chloride, and properties of polyelectrolyte complexes
J. Kleinen, W. Richtering
Colloid and Polymer Science, 289 (5), 739-749 (2011) DOI:10.1007/s00396-011-2401-4

Rearrangements in and Release from Responsive Microgel−Polyelectrolyte Complexes Induced by Temperature and Time
J. Kleinen, W. Richtering
J. Phys. Chem. B, 115 (14), 3804-3810 (2011)   DOI:10.1021/jp2014594

Influence of Architecture on the Interaction of Negatively Charged Multisensitive Poly(N-isopropylacrylamide)-co-Methacrylic Acid Microgels with Oppositely Charged Polyelectrolyte: Absorption vs Adsorption
J. Kleinen, A. Klee, W. Richtering
Langmuir, 26 (13), 11258–11265 (2010)   DOI:10.1021/la100579b

Study of Layer-by-Layer Films on Thermoresponsive Nanogels Using Temperature-controlled Dual-Focus Fluorescence Correlation Spectroscopy
J. E. Wong, C. B. Müller, A. M. Díez-Pascual, W. Richtering
J. Phys. Chem. B, 113(49), 15907–15913 (2009)   DOI:10.1021/jp903941c

Layer-by-Layer Assembly of Polyelectrolyte Multilayers on Thermoresponsive P(NiPAM-co-MAA) Microgel: Effect of Ionic Strength and Molecular Weight
J. E. Wong, A. M. Diez-Pascual, W. Richtering
Macromolecules, 42, 1229–1238 (2009)   DOI:10.1021/ma802072c

Dual-stimuli responsive PNiPAM microgel achieved via layer-by-layer assembly: Magnetic and thermoresponsive
J. E. Wong, A. K. Gaharwar, D. Müller-Schulte, D. Bahadur, W. Richtering
J. Colloid Interf. Sci. 324 (1-2), 47-54 (2008)   DOI:10.1016/j.jcis.2008.05.024

Surface Modification of Thermoresponsive Microgels via Layer-by-Layer Assembly of Polyelectrolyte Multilayers
J. E. Wong, W. Richtering
Progr. Colloid Polym Sci. 133, 45-51 (
2006)   DOI:10.1007/3-540-32702-9_8

Influence of polyelectrolyte multilayer adsorption on the temperature sensitivity of poly(N-isopropylacrylamide) (PNiPAM) microgels
N. Greinert, W. Richtering
Colloid Polym. Sci. 282, 1146-1149,
(2004)  DOI:10.1007/s00396-004-1048-9