Two main topics are addressed in this dissertation: (1) adhesion in hydrogels; (2) interfacial interactions between model glassy polymers. A self-assembly technique for the formation of hydrogels from acrylic triblock copolymer solutions was developed, based on vapor phase solvent exchange. Structure formation in the gels was characterized by small angle X-ray scattering, and swelling was measured in controlled pH buffer solutions. Strong gels are formed with polymer weight fractions between 0.01 and 0.15, and with shear moduli between 0.6 kPa and 3.5 kPa. Adhesive functionality, based on 3,4-dihydroxy-L-phenylalanine (DOPA) was also incorporated into the triblock copolymers. The effect of DOPA concentration on gel formation and swelling was investigated in detail. The adhesive properties of DOPA-functionalized hydrogels on TiO2 were investigated with an axisymmetric adhesion method. It was shown that the presence of DOPA enhances the adhesive properties of the hydrogels, but that the effect is minimized at pH values below 10, where the DOPA groups are hydrophobic. Thin film membranes were produced in order to study the specific interactions between DOPA and TiO2 and DOPA and tissue, using a membrane inflation method. The presence of DOPA in the membranes enhances the adhesion on TiO2 and tissue, although adhesion to tissue requires that the DOPA groups be oxidized while in contact with the tissue of interest. </DISS_para> <DISS_para>Porous hydrogel scaffolds for tissue engineering applications were formed by adding salt crystals to the triblock copolymer solution prior to solvent exchange. Salt was then leached out by immersing the gel into water. Structures of the porous hydrogels were characterized by confocal laser scanning microscopy. These hydrogels were shown to be suitable for tissue regeneration and drug delivery applications. Diffusion-mediated adhesion between two component miscible polymer systems having very different glassy temperatures was also investigated. Axisymmetric adhesion tests were performed on thin layers of poly(tetramethyl bisphenol-A polycarbonate) (TMPC)/poly(ethylene oxide) (PEO) blends with different blend compositions. The tests were designed to investigate the effects of temperature and contact time on interfacial adhesion between two blend surfaces. Adhesion in this system is controlled by diffusive motions of the highly mobile PEO component.

Last modified

• 08/30/2018

Creator

• Murat Guvendiren

DOI

• https://doi.org/10.21985/N2BM7G

Subject

• Materials Science and Engineering

Keyword

• DOPA adhesion
• glassy polymers
• hydrogel scaffolds
• diffusion mediated adhesion
• hydrogel
• Self assembly

Date created

• 2007-08-02

Resource type

• Dissertation

Rights statement

• In Copyright