Harry Allcock

Professional Appointments and Affiliations

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Atherton Professor of Chemistry

Courtesy Appointments in the Departments of Chemical Engineering and Biomedical Engineering

Office 

118 Chemistry Building
University Park, PA 16802

Education

B.Sc., University of London

Ph.D., University of London

Postdoctoral, Purdue University and National Research Council of Canada

Senior Scientist, American Cyanamid Co., Stamford, CT

Sabbatical Positions: Stanford University, Imperial College, London, IBM, Almaden Laboratory, CA

Honors and Awards

International Award of the Polymer Society of Japan (2017)

Elected to the National Academy of Engineering (2014)

American Chemical Society Paul Flory Award in Polymer Education (2010)

American Chemical Society National Award in Applied Polymer Science (2007)

Honorary degree from Loughborough University of Technology, U.K. (2006)

Penn State Graduate Commencement Speaker (1997 & 2005)

American Chemical Society Herman Mark Award in Polymer Chemistry (1994)

American Chemical Society National Award in Materials Chemistry (1992)

American Institute of Chemists Chemical Pioneer Award (1989)

Guggenheim Fellow (1985-1986)

Penn State University, Evan Pugh Professorship (1985-present)

American Chemical Society National Award in Polymer Chemistry (1984)

Research

Application of chemical synthesis to polymer chemistry and materials science; hybrid inorganic - organic materials; correlation of molecular structure with properties for small molecules, bio-medical materials, energy-related materials, phosphorus chemistry, high polymers, solids, and surfaces.

Polymer Synthesis, Materials Chemistry, and Biomedicine

The use of fundamental chemistry to advance the fields of polymers, materials, and biomedicine is a major emphasis in modern research. Professor Harry Allcock and his students are exploring novel approaches to these subjects by the synthesis and study of new classes of high polymers and advanced materials using the techniques of organic, organometallic, and inorganic chemistry.

High polymers are long chain macromolecules that are the constituents of many useful materials. Depending on their molecular structures, different polymers can have properties, such as liquid crystallinity, high strength or elasticity, catalytic activity, unusual optical or electrical properties, or special biomedical qualities.

Most conventional polymers are derived from petroleum. They are inexpensive, but they have a relatively restricted range of properties. For example, in general, they lack the thermal stability of ceramics, the long-term electrical behavior of silicon or metals, the "optical switching" behavior of inorganic solids, or the biocompatibility of living tissues and ceramic materials.

The research in the Allcock group involves the design and synthesis of new polymers that contain organic components, together with heteroelements such as phosphorus, silicon, boron, or transition metals. The aim is to combine the most advantageous properties found in organic polymers with the special properties imparted by the heteroelements. For example, our research team has developed synthesis routes to a broad range of new polymers that have backbones of the types shown in 1-3, and with organic or organometallic side units attached to these backbones. By varying the side group structure, it is possible to bias the properties toward those of elastomers or structural materials, liquid crystalline polymers, semiconductors, high refractive index glasses, ceramics, inert biomedical materials, or biologically active polymers. Other polymers with carbon or sulfur in the backbone, as well as phosphorus and nitrogen, are also under development, in addition to copolymers with organic and silicone macromolecules. (see Diagram)

There are three general aspects to nearly all the research topics in this program:

(1) The development of new synthesis methodology starting at the level of small molecules and progressing to macromolecules. Much of this work involves the development of organic substitution methods or organometallic reaction chemistry, and contains a high component of molecular design based on ongoing structure-property studies.

(2) Characterization and molecular structure determination of the new compounds by techniques such as NMR, IR, gel permeation chromatography, X-ray diffraction, molecular mechanics-molecular graphics, etc. The aim of this aspect is to relate the unique properties found for the new polymers to their molecular structures.

(3) Examination of the materials' properties (i.e., solid state properties) of the new polymers, again with a view to developing structure-property relationships that will aid future research. Techniques such as thermal analysis, electrical and optical behavior, scanning electron microscopy, X-ray photoelectron spectroscopy, and biocompatibility studies are examples of the approaches used. This phase of each project often involves collaborations with other research groups that have specialized experience in materials' or medical-oriented techniques. For instance, our work on nonlinear optical materials, composite materials, ceramics, semiconductors, membranes, bioerodible polymers, bioactive surfaces, fuel cell membranes, and solid polymeric battery electrolytes is conducted through collaborations with groups at other universities and in industrial laboratories. Examples of the medical-oriented research are the development of new polymers for microencapsulation of drugs or vaccines and materials for tissue engineering and bone regeneration.

Overall, the research in this program provides training in the ways that fundamental synthetic, mechanistic, and structural chemistry can be utilized in polymer chemistry and materials science. It also offers opportunities for an understanding of long-range practical topics that a student will almost certainly encounter in a professional scientific career.

Selected Publications

Allcock, H. R. and Chen, C., Polyphosphazenes: Phosphorus in Inorganic-Organic Polymers, J. Org. Chem, Special Issue on Phosphorus Chemistry 2020, 85, 14286-14297.

Tang, M.; Chen, C.; Zhu, J.; Allcock, H. R.; Siedlecki, C. A.; Xu, L.-C. Inhibition of Bacterial Adhesion and Biofilm Formation by a Textured Fluorinated Alkoxyphosphazene Surface, Bioactive Materials, 2021, 6(2): 447-459.

Ogueri, K. Ogueri, K. S.; Laurencin, C. T.; Allcock, H. R. Thiophene-Based Polyphosphazenes with Tunable Optoelectronic Properties – Solution Photophysical Properties and Quantitative Doping, J. Polym. Sci. 2020, 58, 3294-3310.

Xu, L.-C.; Chen, C.; Allcock, H. R.; Siedlecki, C., New Crosslinkable Poly[bis(octafluoropentoxy)phosphazene] Biomaterials: Synthesis, Surface Characterization, Bacterial Adhesion, and Plasma Coagulation Responses, J. Biomed. Mater. Res.: Part B - Applied Biomaterials, 2020,

Li, Z.; Chen, C.; McCaffrey, M.; Yang, H.; Allcock, H. R., Polyphosphazene Elastomers with Alkoxy and Trifluoroethoxy Side Groups, ACS Applied Polymer Materials 2020, 2, 475-480. 2020.

Ogueri,K. S; Ogueri, K. S.; Allcock, H. R.; Laurencin C. T, A Regenerative Polymer Blend Composed of Glycylglycine Ethyl Ester-Substituted Polyphosphazene and Poly (lactic-co-glycolic acid): Preparation, Phase Distribution Morphology, Degradation Mechanism and in Vitro Evaluation. ACS Applied Polymer Materials, 2020, 2, 3, 1169–1179

Allcock, H. R.; Background and Scope of Polyphosphazenes as Biomedical Materials. (Special Issue on Polyphosphazenes edited by A. Andrianov) Regen. Eng. Trans. Med. Medicunehttps://doi.org/10.1007/s40883-019-00128-z 

Allcock, H. R.; Synthesis, Structures, and Emerging Uses for Poly(organophosphazenes). Chapter 1 in Polyphosphazenes in Biomedicine, Engineering & Pioneering Synthesis.             A. Andrianov and H. R Allcock eds.  ACS Symposium Series Books, Online version,    published August 2018, Print version, Oxford University Press, 2019.

Allcock, H. R.  Polyphosphazenes as an Example of the Element Blocks Approach to New Materials. Chapter 10 in New Polymeric Materials Based on Element Blocks,     Chujo, Y., ed., pp. 167-188, 2019, Springer/Nature, Singapore.

Ren, Y.; Kai, Y.; Yang, Shan, D.; Tong, C.; Yang, K.; Shan, D.; Allcock, H. R. Polyphosphazenes and Cyclotriphosphazenes with Propeller-Like Tetraphenylethyleneoxy Side Groups: Tuning Mechanical and Optoelectronic Properties, Macromolecules, 2018, 51, 9974-9981.

Allcock, H. R. (Book) Introduction to Materials Chemistry, 2nd Edition, John Wiley & Sons, Hoboken NJ, 2020, 22 Ch.,487 pp.

Li, Z.; Chen, C; McCaffrey, M; Yang, H.; Allcock, H. R. Polyphosphazene Elastomers with Alkoxy and Trifluoroethoxy Side Groups, ACS     Applied Polymer Materials, in press, January 2020. (#659)

Ogueri, K. S.; Ogueri, K. S.; Allcock, H. R.; Laurencin, C. T. Regenerative Polymer Blend Composed of Glycylglycine Ethyl Ester-Substituted Polyphosphazene and Poly (lactic-co-glycolic acid): Preparation, Phase Distribution, Morphology, Degradation Mechanism and in Vitro Evaluation. ACS Applied Polymer Materials, in press, January 2020

Allcock, H. R. Hybrids of Poly(organophosphazenes) and Poly(organosiloxanes):  A brief Perspective of an Evolving Aspect of Inorganic Polymers, J. Inorg. Orgmet. Polym. and Materials, Anniversary Issue, 2020. In Press

Ogueri, K. S., Allcock, H. R.; Laurencin, C. L., Phosphazene Polymers, Encyclopedia of Polymer Science, 2019, DOI: 10. 1002/04714 40264.

Yennawar, H., Hess, A., Allcock, H. R. Synthesis and X-Ray Crystal Structures of Three Fluoroaryloxy-Cyclotriphosphazenes: Models for the Corresponding High Polymers. Acta Cryst. Part E75, 2019,1525-1530.

Ogieri, K. S.; Allcock, H. R.; Laurencin C. Generational Biodegradable and Regenerative Polyphosphazene Polymers and their Blends with Poly(lactic-co-glycolic Acid), Progress in Polymer Science 2019, 98. #101146, 1-10.

Tong, C.; McCarthy, S.; Li, Z.; Guo, J.; Li, Q.; Pacheco, C. N.; Ren, Y.; Allcock, H. R. Hybrid Polyphosphazene–Organosilicon Polymers as Useful Elastomers, ACS Applied Polymer Materials 2019, 1, 7, 1881-1886.

Ogueri, K. S.; Ivirico. J. E.; Li, Z.; Blumenfield, R. H.; Allcock, H. R.; Laurencin, C. T. Synthesis, Physicochemical Analysis, and Side Group Optimization of Degradable Dipeptide-Based Polyphosphazenes as Potential Regenerative Biomaterials, ACS Applied Polymer Materials 2019, 1568-1578.

Allcock, H. R. Background and Scope of Polyphosphazenes as Biomedical Materials. (Special Issue on Polyphosphazene Biomaterials edited by A. Andrianov). Regen. Eng. Trans. Med. Medicine, https://doi.org/10.1007/s40883-019-00128-z

Allcock, H. R. Polyphosphazenes as an Example of the Element Blocks Approach to New Materials. Chapter 10 in New Polymeric Materials Based on Element Blocks, Chujo, Y., ed., pp. 167-188, 2019, Springer/Nature, Singapore.

Ren, Y.; Kai, Y.; Yang, Shan, D.; Tong, C.; Yang, K.; Shan, D.; Allcock, H. R. Polyphosphazenes and Cyclotriphosphazenes with Propeller-Like Tetraphenylethyleneoxy Side Groups: Tuning Mechanical and Optoelectronic Properties, Macromolecules, 2018, 51, 9974-9981.

Allcock, H. R. Synthesis, Structures, and Emerging Uses for Poly(organophosphazenes). Chapter 1 in Polyphosphazenes in Biomedicine, Engineering & Pioneering Synthesis. Andrianov, A. and Allcock, H. R. eds.  ACS Symposium Series Books, Online version, published August 2018, Print version, Oxford University Press, 2019.