PoIy(styrene-block-1,2-butadiene) Block Copolymers Functionalized with Ferrocenylsilane Units

Significance of the topic

The functionalization of block copolymers with redox‐active ferrocenylsilane units addresses growing demands in biosensor design and advanced materials. By integrating organometallic functionality into polymer backbones, researchers can tailor electronic, optical and interfacial properties critical for sensitive detection platforms and smart materials.

Study objectives and overview

This study aimed to graft HSiMe2Fc ferrocenylsilane onto polystyrene‐block‐1,2‐butadiene (PS‐b‐PB) prepared by anionic polymerization via Karstedt‐catalyzed hydrosilylation. Key goals were to confirm quantitative functionalization, characterize molecular weights and polydispersity before and after reaction, and identify side reactions affecting product distribution.

Methodology and instrumentation

The polymer and its functionalized derivative were analyzed using complementary techniques:

• Size Exclusion Chromatography (SEC) with polystyrene standards
• Multi‐Angle Light Scattering (MALS) in THF, online detection
• Membrane Osmometry for absolute molecular weight
• 1H‐NMR spectroscopy for composition and conversion assessment
• Hydrosilylation under Karstedt catalyst conditions for grafting

Main results and discussion

SEC data calibrated against polystyrene standards underestimated the molecular weight of the ferrocenylsilane‐grafted polymer, suggesting unchanged hydrodynamic radius. In contrast, MALS measurements revealed a significant increase in Mn and Mw after functionalization (from ≈66 930 to 87 100 g/mol Mn by MALS). 1H‐NMR confirmed complete double bond conversion and quantitative introduction of HSiMe2Fc units. A broader polydispersity index and the appearance of a peak at double molecular weight indicate side reactions—primarily crosslinking and dimerization of unreacted butadiene segments under hydrosilylation.

Benefits and practical applications

The successful attachment of ferrocenylsilane imparts redox activity and enhanced interfacial properties to the block copolymer, making it a promising candidate for:

• Biosensor electrodes with tunable electron transfer
• Electroactive coatings and membranes
• Stimuli-responsive materials for diagnostics

Future trends and possibilities

Ongoing research will extend functionalization to PS‐b‐PB with higher butadiene content, potentially amplifying redox sensitivity and mechanical flexibility. Integration into microelectrode arrays, conductive hydrogels or nanostructured sensor surfaces is anticipated. Advanced monitoring by real-time light scattering and electrochemical methods will further elucidate reaction kinetics and polymer architecture.

Conclusion

This work demonstrates a straightforward, high‐yield route to ferrocenylsilane‐functionalized block copolymers. Combined light scattering and NMR methods provided robust characterization, while side‐reaction analysis highlighted areas for process optimization. The resulting materials open avenues for next‐generation biosensors and electroactive polymer applications.