Applications of Polyhedral Oligomeric Silsesquioxanes

Foreword: The Re-Birth of PolyhedralOligosilsesquioxane Chemistry

Preface

Biographical Note

Contents

Contributors

Chapter 1 Polyhedral Oligomeric Silsesquioxanes: From Early and Strategic Development through to Materials Application

1.1 Introduction

1.2 Early Synthesis of Polyhedral Oligosilsesquioxanes (POS)

1.3 Hydrolysis and Condensation in Making Oligosilsesquioxanes

1.4 Synthesis of Hydridooctasilsesquioxane, H8Si8O12 (T8H8) and Octakis-(Hydridodimethylsiloxy)Octasilsesquioxane, [H(CH3)2SiO]8Si8O12 (Q8M8H8)

1.5 Hydrosilylation

1.6 Octa-Functionalized POS Macromonomers

1.6.1 Macromonomers Derived by the Hydrosilylation of Octahydridosilsesquioxane (H8Si8O12

1.6.2 Macromonomers Derived by the Hydrosilylation of Octa(Hydridodimethylsiloxy)Octasilsesquioxane[(HSiMe2O)8Si8O12

1.7 Organic-Inorganic Hybrid Materials Prepared from POS: Octasilsesquioxanecontaining Polymers

1.7.1 Hybrid Organic-Inorganic Crosslinked Materials Containing POS

1.7.2 Star-Shaped Hybrid Organic-Inorganic Materials Containing POS as a Macroinitiator

1.8 Mono-Substituted Polyhedral Oligomeric Silsesquioxane Macromonomers

1.8.1 Synthesis of Mono-Substituted Silsesquioxanes by Hydrolysis of Trifunctional Silanes

1.8.2 Synthesis of Mono-Substituted Silsesquioxanes by Hydrosilylation

1.8.3 Synthesis of Mono-Substituted Silsesquioxanes by Corner-Capping Reactions

1.9 Chemistry of Incompletely Condensed Silsesquioxanes

1.9.1 Synthesis of Incompletely Condensed Silsesquioxanes

1.9.2 Chemistry of Incompletely Condensed Silsesquioxanes

1.9.3 Hybrid Organic-Inorganic Materials Derived from Mono-Substituted POS Monomers

1.10 Summary

1.11 References

Chapter 2 Preparation and Characterization of Polyhedral Oligosilsesquioxanes

2.1 General Comments

2.2 Synthesis of TnRn Compounds where R = H, Alkyl or Alkenyl

2.2.1 Hydrolysis

2.2.1.1 T4 and T6 Compounds

2.2.1.2 T8 Compounds

2.2.1.3 T10, T12 and Larger Compounds

2.2.2 Substitution

2.2.3 Cage Rearrangement

2.2.4 Modification of R

2.2.4.1 T8 Compounds

2.2.4.2 T10 and T12 Compounds

2.2.5 Other Synthetic Methods

2.2.5.1 T6 Compounds

2.2.5.2 T8 Compounds

2.2.5.3 T10 and T12 Compounds

2.3 Synthesis of TnRn Compounds where R = Aryl

2.3.1 Hydrolysis

2.3.1.1 T8 Compounds

2.3.1.2 T10 and T12 Compounds

2.3.2 Modification of R

2.3.2.1 T8 Compounds

2.3.2.2 T10 and T12 Compounds

2.3.3 Other Synthetic Methods

2.4 Synthesis of Tn Rn Compounds where R =Alkoxy

2.5 Synthesis of TnRn Compounds whereR = Siloxy

2.5.1 Corner Capping

2.5.2 Substitution

2.5.2.1 T8 Compounds

2.5.2.2 T10, T12, and T14 Compounds

2.5.3 Modification of R

2.5.3.1 T6 Compounds

2.5.3.2 T8 Compounds

2.5.3.3 T10 Compounds

2.6 Synthesis of TnRn Compounds where R = Metal Complex

2.6.1 Hydrolysis

2.6.2 Substitution

2.6.2.1 T8 Compounds

2.6.2.2 T10 Compounds

2.6.3 Modification of R

2.7 Synthesis of Miscellaneous TnRn Compounds

2.7.1 Hydrolysis

2.7.1.1 T6 Compounds

2.7.1.2 T8 Compounds

2.7.1.3 T10 Compounds

2.7.2 Co-Hydrolysis

2.7.3 Substitution and Modification of Functional Groups

2.7.4 Other Synthetic Methods

2.7.4.1 T4 Compounds

2.7.4.2 T8 Compounds

2.7.4.3 T10 Compounds

2.8 Synthesis of Endohedral T8R8 Compounds

2.9 Introduction to the Physical Properties of POS Compounds

2.10 NMR and EPR Spectroscopy of POS Compounds

2.10.1 Solution 29Si NMR Studies

2.10.2 Solid State NMR Studies

2.10.3 EPR Spectra

2.11 Vibrational Spectra of Polyhedral Oligomeric Silsesquioxane Compounds

2.12 Mass Spectra of POS Compounds

2.13 Electronic Spectra of POS Compounds

2.14 Structural Studies of POS Compounds

2.14.1 Single Crystal X-Ray Diffraction Studies

2.14.2 Structures Derived from Computational and Gas-Phase Electron Diffraction Studies

2.14.3 X-ray Diffraction Studies on Powders, Thin Films, etc.

2.14.3.1 T8R8 Compounds

2.14.3.2 T8R7R’ Compounds

2.15 TGA, DSC and Related Studies of POS Compounds

2.15.1 T8R8 Compounds (R = H, Alkyl, Vinyl, Aryl or Silyl Derivatives)

2.15.2 T8R8 Compounds (R = Siloxy Derivatives)

2.15.3 T8R7R’ Compounds

2.16 Microscopy Studies of T8 POS Compounds

2.16.1 T8R8 Compounds

2.16.2 T8R7R’ Compounds

2.17 X-Ray Photoelectron Spectra of POS Compounds

2.18 Electrochemistry of POS Compounds

2.19 Chromatographic Methods Applied to POS Compounds

2.20 Miscellaneous Physical Properties of POS Compounds

2.21 Acknowledgments

2.22 References

Chapter 3 Metallasilsesquioxanes: Molecular Analogues of Heterogeneous Catalysts

3.1 Introduction

3.2 Metallasilsesquioxanes

3.2.1 Group 4 – Ti, Zr, Hf

3.2.2 Group 5 – V

3.2.3 Group 6 – Mo

3.2.4 Group 8 – Fe

3.2.5 Group 12 – Zn

3.2.6 Group 13 – Al

3.2.7 Group 14 – Si

3.2.8 Lanthanides – Nd

3.2.9 Hetero-bimetallic Systems

3.3 Phosphasilsesquioxanes as Ligands

3.4 Catalytic Materials Derived From Metalla-Silsesquioxanes

3.5 Conclusions and Future Prospects

3.6 References

Chapter 4 Polymers and Copolymers Containing Covalently Bonded Polyhedral Oligomeric Silsesquioxanes Moieties

4.1 Introduction

4.2 Synthetic Strategies

4.2.1 Free Radical Polymerization

4.2.2 Living Radical Polymerization (ATRP, RAFT and NMP)

4.2.3 Anionic Polymerization

4.2.4 Ring-Opening Metathesis Polymerization (ROMP)

4.2.5 Metallocene-Catalyzed Polymerization

4.2.6 Step-Growth Polymerization

4.2.7 Grafting

4.3 POS Pendant-Random Copolymers

4.3.1 Glass Transition Temperature

4.3.2 Mechanical Properties

4.3.3 Crystallinity in POS Pendant-Random Copolymers

4.4 POS Pendant-Block Copolymers

4.4.1 Diblocks

4.4.2 Triblocks

4.4.3 Hemitelechelic (‘Tadpole’-Shaped) Polymers

4.4.4 Telechelic (Dumbbell-Shaped) Polymers

4.5 POS-Polyimide and POS-Urethanes

4.5.1 POS-Polyimide

4.5.2 POS-Urethane

4.6 Multifunctional POS in Network or Core Structures

4.6.1 Epoxy Networks

4.6.2 Other POS Networks

4.6.3 POS Star or Core Structures

4.7 Conclusion

4.8 References

Chapter 5 Polyhedral Oligomeric Silsesquioxanes in Plastics

5.1 Introduction

5.2 POS are Molecules

5.3 POS as Plastics Additives

5.4 POS Solubility

5.5 Effects of POS on Polymer Properties

5.5.1 POS Solubilized in the Polymer

5.5.2 POS Insoluble Present at Concentrations Above the Solubility Limit

5.5.3 POS Chemically Attached to the Polymer

5.5.4 POS Network Thermosets

5.6 POS Dispersants

5.7 POS Metal Deactivators

5.8 New Applications and the Future

5.9 Conclusions

5.10 References

Chapter 6 Fluorinated Polyhedral Oligosilsesquioxane Surfaces and Superhydrophobicity

6.1 Introduction

6.2 Experimental

6.2.1 Materials

6.2.2 Single Crystal X-Ray Structural Characterization

6.2.3 Fluorinated POS Coating and Composite Preparation

6.2.3.1 Spin Cast Fluorinated POS Coating

6.2.3.2 Fluorinated POS Solvent Blended Composites with 6F-BP PFCB Aryl Ether Polymer

6.2.3.3 Fluorinated POS Melt Blended PCTFE

6.2.4 Thermo-Mechanical Analysis

6.2.5 Microscopy

6.2.5.1 Atomic Force Microscopy (AFM)

6.2.5.2 Scanning Electron Microscopy (SEM)

6.2.6 Static and Dynamic Contact Angle

6.3 Results and Discussion

6.3.1 Fluorinated POS Synthesis

6.3.2 Fluorinated POS Properties

6.3.3 POS Fluoropolymers

6.3.3.1 Dispersion

6.3.3.2 Melt Processability

6.3.3.3 Thermo-Mechanical Analysis

6.3.3.4 Surface Properties

6.4 Conclusions

6.5 Acknowledgments

6.6 References

Chapter 7 Polyhedral Oligomeric Silsesquioxanes in Electronics and Energy Applications

Introduction

7.1 Polyhedral Oligomeric Silsesquioxanes in Liquid Crystal Systems

7.2 Polyhedral Oligomeric Silsesquioxanes in Electroluminescent (EL) Materials and Light Emitting Devices (LEDs)

7.2.1 Polyhedral Oligomeric Silsesquioxane End-capped EL Polymers

7.2.2 EL Polymers with Pendant Polyhedral Oligomeric Silsesquioxane Groups

7.2.3 EL Star Architectures with Polyhedral Oligomeric Silsesquioxane Cores

7.2.4 Polyhedral Oligomeric Silsesquioxane Iridium Complexes

7.2.5 Physical Blending of Polyhedral Oligomeric Silsesquioxanes into EL Polymers

7.3 Polyhedral Oligomeric Silsesquioxanes in Non-linear Optic (NLO), Optical Limiting (OL) and Laser Applications

7.4 Polyhedral Oligomeric Silsesquioxanes in Lithographic Applications

7.5 Polyhedral Oligomeric Silsesquioxanes in Sensor Systems

7.5.1 Fluorophore-Functionalized Polyhedral Oligomeric Silsesquioxanes as Sensors

7.5.2 Polyhedral Oligomeric Silsesquioxane Sensors for Gas and Vapor Detection

7.5.3 Polyhedral Oligomeric Silsesquioxanes in Conducting Composite and Electrochemical Sensors

7.6 Polyhedral Oligomeric Silsesquioxanes in Fuel Cell Applications

7.7 Polyhedral Oligomeric Silsesquioxanes in Battery Applications

7.8 Polyhedral Oligomeric Silsesquioxanes as Lubricants

7.9 References

Chapter 8 Polyhedral Oligomeric Silsesquioxanes in Space Applications

8.1 The Space Environment

8.2 Resistance of Siloxane Copolymers to Atomic Oxygen in Low Earth Orbit

8.3 Polyhedral Oligomeric Silsesquioxanes in Space Solar Power Systems

8.4 Summary

8.5 References

Chapter 9 Biomedical Application of Polyhedral Oligomeric Silsesquioxane Nanoparticles

9.1 Introduction

9.2 Nanocomposites

9.3 Polyhedral Oligomeric Silsesquioxanes

9.4 Biomedical Applications of Polyhedral Oligomeric Silsesquioxane-Containing Polymers

9.4.1 Drug Delivery

9.4.2 Dental Nanocomposites

9.4.3 Biosensors

9.4.4 Cardiovascular Implants

9.4.4.1 Mechanical Properties

9.4.4.2 Degradative Resistance

9.4.4.3 Biocompatibility and Biostability

9.4.4.4 Endothelialization Property

9.4.4.5 Anti-Thrombogenic Potential

9.4.4.6 Resistance to Calcifi cation and Fatigue

9.4.4.7 Reduced In Vitro Infl ammatory Response

9.4.5 Breast Implants

9.4.6 Coating Material for Quantum Dot Nanocrystals

9.4.7 Silver Nanoparticle-Containing Polyhedral Oligosilsesquioxane Polymers

9.4.8 Tissue Engineering

9.5 Other Applications

9.6 Future Prospects

9.7 References

Index

Abbreviations