Surface-Initiated Polymerizations Mediated by Novel Germanium-Based Photoinitiators

Area of Science:

• Materials Science
• Polymer Chemistry
• Surface Science

Background:

• Surface-initiated photopolymerization is crucial for advanced material functionalization.
• Covalently coupled photoinitiators enable diverse surface properties like wettability and drug delivery.
• Existing photoinitiators have limitations, driving the search for novel compounds.

Purpose of the Study:

• To synthesize and characterize a novel germanium-based photoinitiator.
• To demonstrate the immobilization of this photoinitiator onto surfaces.
• To utilize the photoinitiator for visible-light-triggered surface-initiated polymerization and create functional surfaces.

Main Methods:

• Synthesis of bromo-tris(2,4,6-trimethylbenzoyl)germane.
• Immobilization onto silicon wafers and quartz plates, confirmed by X-ray photoelectron spectroscopy (XPS).
• Surface-initiated polymerization of functional monomers (acrylamide, perfluorodecyl acrylate, fluorescein-o-acrylate) using visible light.

Main Results:

• Successful synthesis of the novel germanium-based photoinitiator in good yields.
• Confirmed immobilization of the photoinitiator on silicon wafer and quartz surfaces via XPS.
• Creation of surfaces with tunable hydrophilic/hydrophobic and fluorescent properties through controlled polymerization.
• Characterization of polymer layers (10-126 nm thickness) using contact angle, spectroscopy, ellipsometry, and XPS.

Conclusions:

• The novel germanium-based photoinitiator is effective for visible-light-triggered surface-initiated photopolymerization.
• This method allows for the creation of precisely functionalized surfaces with tailored properties.
• The developed technique offers a versatile platform for advanced surface engineering in materials science.