Polyelectrolyte Self-Assembly: Multilayers, Coacervates and Hydrogels




The ‘Layer-by-layer’ (LbL) method allows the self-assembly of polyelectrolyte multilayers by alternating adsorption of polyanions and polycations to interfaces, providing a route towards versatile materials with structures defined on a nanometer scale. Such ultrathin LbL-films are allowing incorporation of various molecular or ionic constituents. In particular, we include various functionalities into LbL films towards potential applications. Examples are selective binding sites for small molecules formed by surface molecular imprinting, Au nanoparticles yielding films with humidity-tunable electronic conductivity, and weak polyacids allowing manipulation of the charge balance by pH variation to control ion content and ionic conductivity.

Furthermore, from the more fundamental angle of polymer physics, we are investigating dynamics and transport processes in ionic 3D polymer systems. Polyelectrolyte complexes formed from polycations and polyanions are the analogue 3D material to multilayers. They can form solid complexes or strongly water-swollen complex coacervate phases. Frequency-dependent rheology and impedance spectroscopy data deliver detailed dynamic information, leading to general laws, such as time-temperature superposition, or, in analogy, novel time-humidity superposition or time-pH superposition laws were identified. Currently we extend these activities to biopolymer systems and other types of (for example self-healing) hydrogels.

© M. Schönhoff
© M. Schönhoff

Relevant preliminary work:


  1. Composition and Charge Compensation in Chitosan – Gum Arabic Complex Coacervates in Dependence on pH and Salt Concentration Schröder P, Cord-Landwehr S, Schönhoff M, Cramer C Biomacromolecules 24 (3), 1194-1208 (2023)
  2. Modelling viscoelastic relaxation mechanisms in thermorheologically complex Fe(III)-poly(acrylic acid) hydrogels
    Lenoch, A.; Schönhoff, M.; Cramer, C. Soft Matter 18, 8467 – 8475 (2022)

  3. Quantification of chitosan in aqueous solutions by enzymatic hydrolysis and oligomer analysis via HPLC-ELSD
    Schröder P, Wattjes J, Schönhoff M,  Moerschbacher B, Cord-Landwehr S, Cramer C Carbohydrate Polymers 283, 119141 (2022)

  4. Ionic conductivity of solid polyelectrolyte complexes with varying water content: application of the dynamic structure model
    Ostendorf A, Schönhoff M, Cramer C. Phys. Chem. Chem. Phys. 21(14), 7321-7329 (2019)
  5. Quantifying and controlling the cation uptake upon hydrated ionic liquid-induced swelling of polyelectrolyte multilayers
    Parveen N, Schönhoff M. Soft Matter 13(10), 1988-1997 (2017)
  6. Cucurbit[8]uril-containing multilayer films for the photocontrolled binding and release of a guest molecule
    Nicolas H, Yuan B, Zhang X, Schönhoff M. Langmuir 32, 2410-2418 (2016)
  7. pH-dependent growth laws and viscoelastic parameters of poly-L-lysine/ hyaluronic acid multilayers
    Bütergerds D, Cramer C, Schönhoff M.  Adv. Mater. Interfaces 4(1), 1600592 (2017)
  8. Scaling properties of the shear modulus of polyelectrolyte complex coacervates: A time-pH superposition principle
    Tekaat M, Bütergerds D, Schönhoff M, Fery A, Cramer C.  Phys. Chem. Chem. Phys. 17, 22552-22556 (2015)