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Published on: September 29, 2015
Ionically Paired Layer-by-Layer Hydrogels: Water and Polyelectrolyte Uptake Controlled by Deposition Time
Victor Selin1, John F Ankner2, Svetlana A Sukhishvili3
1Department of Materials Science & Engineering, Texas A&M University, College Station, TX 77843, USA. vselin@tamu.edu.
Longer deposition times for polyelectrolyte multilayers increase film thickness, swelling, and intermixing. These more intermixed films show reduced stability but faster penetration, impacting biomedical applications.
Area of Science:
- Materials Science
- Polymer Science
- Nanotechnology
Background:
- Weakly bound nonlinear multilayers are of recent interest.
- Structure-property relationships in these films are poorly understood.
Purpose of the Study:
- To investigate the effect of deposition time on nonlinear layer-by-layer (LbL) film properties.
- To understand how deposition time influences film structure, swelling, stability, and penetration.
Main Methods:
- Layer-by-layer (LbL) film fabrication using poly(methacrylic acid) (PMAA) and quaternized poly-2-(dimethylamino)ethyl methacrylate (QPC).
- Spectroscopic ellipsometry for thickness measurements.
- Neutron reflectometry (NR) for internal structure analysis.
- Fourier-transform infrared spectroscopy (FTIR) for degree of ionization.
Main Results:
- Increased deposition time led to thicker films with higher swelling ratios (up to 4).
- Longer deposition times enhanced film intermixing.
- More intermixed films exhibited greater swelling, lower stability in salt solutions, and faster polyelectrolyte penetration.
Conclusions:
- Deposition time is a critical parameter controlling the structure and properties of nonlinear LbL films.
- Film intermixing, influenced by deposition time, dictates swelling, stability, and permeability.
- Findings are valuable for designing polyelectrolyte nanoassemblies for biomedical applications.
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