Ind. Eng. Chem. Res. 2009, 48, 2301–2304
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Industrial-Academic Partnership: Interdisciplinary Educational Program in Nanoparticles, Macromolecules, and Interfaces Ethel Z. Casassa,† Annette M. Jacobson,* Rosemary Frollini, and Susana C. Steppan Department of Chemical Engineering, Colloids, Polymers and Surfaces Program, Carnegie Mellon UniVersity, Pittsburgh, PennsylVania 15213
The Colloids, Polymers and Surfaces (CPS) Program at Carnegie Mellon provides education about technology applications for nanomaterials, macromolecules, and interfaces. (The CPS Program predates the coining of the term “nano” used in reference to the colloidal size domain. For the purposes of this article, the terms nanoparticles, macromolecules, and interfaces are used synonymously with colloids, polymers, and surfaces, respectively). This program has developed and improved over the past 37 years for two main reasons: (1) continued interest from industry to hire graduates with this background and to provide financial support for part-time students employed locally to enroll in the program and (2) sustained expertise and commitment of faculty in these research areas. The coursework includes the physical chemistry of colloids and polymers, coupled with an intensive laboratory experience that provides exposure to examples of products and processes used in industry. Recently, the program was expanded to include a minor in CPS that is available to all engineering majors. In addition, a new graduate-level course was introduced, offering advanced experimental techniques used to study colloids and polymers. A review of the program content is presented. This article describes how a novel program designed to enhance education in engineering developed and is sustained because of an alliance formed between industry and academia. History of the Program During the first half of the 20th century, academic researchers arrived at important insights into the complex physical and chemical phenomena displayed by fine dispersions of matter in liquid or gaseous media (colloids) and by macromolecules (polymers) whose molecular dimensions fall in the realm of colloidal particle size. Because much of the behavior of colloidal dispersions derives from high surface-to-volume ratios, the related field of surface science also enjoyed major development. Contributions by a number of scientists in these emerging fields were honored with Nobel prizes in chemistry or physics. By midcentury, however, academic chemistry departments largely ignored polymer and colloid science as too complex to allow rigorous scientific analysis or too applied to be proper academic pursuits. Indeed, further progress in these fields required a multidisciplinary approach uncommon at that time. Because of the key role of colloids, polymers, and surfaces in most industrial operations, the lack of an ongoing academic base led the largest companies to invest heavily in their own research and development (R&D) efforts, which produced substantial benefits in processing methods and product innovation. With few exceptions, however, proprietary considerations forbade dissemination of the results of such research, which thus had little impact on the general state of knowledge or on academic education and research. By the 1970s, many industries felt the pinch of rising R&D costs, which included extensive in-house training of newly hired B.S., M.S., and Ph.D. chemists and engineers whose university experience included little or no exposure to basic science governing colloid and polymer phenomena. The very few universities offering courses relevant to industrial problems focused upon a single area, i.e., colloid, polymer, or surface science. Eight major industries in the vicinity of Pittsburgh were * To whom correspondence should be addressed. E-mail: jacobson@ andrew.cmu.edu. † Deceased, March 2003.
at that time operating their own research laboratories. Warnings were sounded from all sides, from the National Science Foundation as well as university sources, under such headlines as “Wake Up and Smell the Coffee!”1 and “ColloidssThe World of Neglected Dimensions”.2 The late Dr. Howard Gerhart, then vice president for R&D at PPG Industries and later adjunct professor of chemical engineering at Carnegie Mellon University, took the lead in approaching Carnegie Mellon with specifics of his company’s needs in basic training and continuing education for technical employees. His requirements fit well with existing planning by the polymer research group of the chemistry department to launch a graduate curriculum in polymers and by the chemical engineering department to introduce colloid and surface science as a focus for graduate study. The result was a new interdisciplinary academic program titled “Colloids, Polymers and Surfaces”, beginning with lecture courses in 1972 and handson laboratory courses, developed under the leadership of the late Professor Ethel Z. Casassa, introduced in 1974. The CPS Laboratory was designed to serve as a resource for the study of colloids, polymers, and surfaces for the university as a whole. Laboratory equipment was funded by grants from the Pennsylvania Science and Engineering Foundation and the Processing Research Institute at Carnegie Mellon, which was supported by the National Science Foundation’s Research Applied to National Needs program to foster industry-academic collaboration in graduate education and research.3 This program offered an M.S. degree to students with a B.S. in an engineering or science field, most specifically to chemists and chemical engineers. On the academic side, it was a cooperative effort under the direction of Professor D. Fennell Evans, employing personnel and physical resources from both the chemistry and chemical engineering departments. Input of R&D supervisors from eight local industries came from the Advisory Board, who participated in major policy decisions and periodic reviews and encouraged qualified employees to take advantage of this unique
10.1021/ie8005148 CCC: $40.75 2009 American Chemical Society Published on Web 11/13/2008
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educational opportunity, with tuition underwritten entirely or partially by the employer. An important industrial contributor to the program was the late Jerome Seiner, Director of Advanced Coatings Research and Corporate Fellow at PPG Industries, CPS Program Advisory Board Member (1974-1998), and former Associate Editor of Industrial & Engineering Chemistry Research. He was a member of the faculty steering committee that planned curriculum, directed admissions, and certified completion of degree requirements. We recognize the continued and sustained support of the CPS Program by Professor John L. Anderson, from 1976 to 2004. He was a firm advocate for rigorous academic standards as Department Head of Chemical Engineering and later Dean of the College of Engineering at Carnegie Mellon. His commitment to the program’s vision and purpose was essential to its growth and continued success. Throughout all these years, there was continuous involvement from alumni of the CPS program working in industry, in the form of hiring our graduates. There is additional support by local companies, providing the opportunity for their employees to take the CPS coursework on a part-time basis. From 1998 to 2003, the PPG Industries Foundation provided financial assistance in the form of grants for laboratory renovation, equipment, and graduate student support. In 2001, the CPS Laboratory was named the PPG Industries Colloids, Polymers and Surfaces Laboratory in recognition of these generous contributions. This industrial funding was leveraged to obtain an NSF instrumentation grant in 1998, which provided additional resources for new laboratory equipment. Program Content and Philosophy The rationale for combining the three areas of colloid, polymer, and surface science in a single curriculum addresses problems not of traditional industries alone, but of emerging high technologies in medical, biological, and interfacial science. Surface chemistry deals with interactions at boundaries where two phases meet. Both equilibrium states and kinetic events at such interfaces depend on the phenomena of surface tension, adsorption and desorption, condensation and evaporation, and the like. Colloid chemistry deals with materials dispersed in a continuous medium in units with sizes ranging from 10-7 to 10-4 cm. Colloidal units in dispersions can be single particles containing many molecules (as in condensed solids or liquids) or aggregates of many molecules in thermodynamic equilibrium (as in micellar surfactants) or of subunits that are actually joined by covalent bonds (as in macromolecules or polymers of natural or synthetic origin). The science of polymer chemistry involves the synthesis and characterization of large, covalently bonded molecules, also referred to as macromolecules. What colloidal systems have in common, and what links them to surface chemistry, are the peculiar properties that follow from the presence of a material boundary or discontinuity of submicroscopic scale and the high ratio of surface to mass that prevails when matter is finely subdivided. Some of the interesting properties of colloidal dispersions are enhanced physical and chemical reactivity, scattering of light, hydrodynamic properties, and osmotic and electrical phenomena. Polymer physical chemistry, a historical offshoot of colloid chemistry, employs many of the same methods of experimentation that are useful for colloids in general. There is a certain cohesion in the common intellectual framework of thermodynamics and statistical mechanics, useful in attacking most problems confronting researchers in colloids, polymers, and surfaces. Exclusion of any one of the three areas removes at the same time a
substantial zone of overlap wherein lie some of today’s most exciting and difficult challenges. The educational focus of the CPS core courses is to teach theoretical chemical and physical concepts that account for the properties of polymers and colloids, including the critical role of surface phenomena. This is accomplished by two physical chemistry lecture courses, one covering colloids and surfaces and the other polymers, followed by two laboratory courses in colloid and polymer characterization techniques. The Physical Chemistry of Colloids and Surfaces lecture course includes topics such as thermodynamics of surfaces; adsorption at gas, liquid, and solid interfaces; capillarity; wetting, spreading, lubrication, and adhesion; properties of monolayers and thin films; preparation and characterization of colloids; and colloidal stability, flocculation kinetics, micelles/association colloids, electrokinetic phenomena, and emulsions. 4,5 The Physical Chemistry of Macromolecules lecture course covers methods for synthesis, processing, and testing of polymers that are currently used in industry including topics such as physical, chemical, and mechanical properties and the relationship of these properties to chain structure and molecular weight, glass transition temperature, rubber elasticity, and polymer rheology.6,7 Applications of the theoretical principles covered in the lecture courses involving the characterization and manipulation of complex systems, which confront industry in everyday production, development, and trouble-shooting, are the tools that students gain from this experience. The requirement of a full year of laboratory training is meant not to turn out accomplished technicians, but to reinforce, extend, and make tangible the theory that has been learned. It has the further practical value of showing students what can be learned from the appropriate design and choice of investigational tools, with full appreciation of both the power and the limitations of available modern methods. Students describe the CPS laboratory exercises as “hands-on theory”, a union of theoretical framework and experimental technique. Each experiment is designed to explore aspects of the principles covered in the lecture courses. Colloids, polymers, and surfaces are evaluated and characterized using state-of-theart instruments located in a 2200 ft2 laboratory facility that is used for both teaching and research. An elective undergraduate four-course sequence in Colloids, Polymers and Surfaces (CPS) was initiated for chemical engineering undergraduate students in 1978. It followed logically from the introduction of the graduate program in 1972. In 2003, the CPS coursework sequence was offered as a minor to all engineering undergraduates at Carnegie Mellon, with the purpose of providing these topics to an increasing audience of students interested in engineering applications of nanomaterials and macromolecules. The initial set of classical experiments was developed over 30 years ago by Professor Casassa and Rosemary Frollini to complement topics covered in the physical chemistry courses; these experiments continue to serve the program well and have been adapted over the years to involve new equipment, new techniques, and current applications. Experiments are added to the curriculum with the acquisition of instruments that reflect current and expanded research expertise by the faculty. Presently, two semesters of laboratory courses are offered to undergraduates, and three are offered to graduate students. A brief description of the experiments comprising the classical colloids and polymer laboratory courses is given in Tables 1 and 2. Most of the laboratory exercises contain topics that are explored more than once during the course. Concepts are
Ind. Eng. Chem. Res., Vol. 48, No. 5, 2009 2303 Table 1. Experimental Colloid and Surface Science Experiment Title Surface Tension Determinations by the Dipping Ring Method Contact Angle Determination by the Sessile Drop Method
Critical Micelle Concentration of a Surfactant Solution
Surface Area of a Powder by Gas Adsorption
Surface Area of a Porous Solid by Adsorption from Solution
Adsorptive Bubble Separation
Colloidal Stability
Coefficient of Friction
Particle Size Characterization
Scanning Tunneling Microscopy (STM)
Description Pure liquids, solutions, and liquid-liquid interfaces are studied. Equilibrium contact angles of liquids are measured, and critical surface tensions of wetting of polymer surfaces are determined. Critical micelle concentration of an ionic surfactant is determined through dye solubilization, conductance, surface tension, and foaming behavior. The specific surface area of a fine powder is determined by measuring the adsorption of nitrogen and then constructing a Brunauer-Emmett-Teller (BET) isotherm. Equilibrium concentrations of a series of acidic solutions are obtained by computer-assisted titration and used to construct a Langmuir isotherm. The concentration gradient in a bubble fractionation column is determined spectrophotometrically, and the thermodynamic and transport properties are studied. A river-water treatment simulation, using clay dispersions treated with polyelectrolytes, is used to study electrical repulsion of charge-bearing particles. The compression of the electric double layer and neutralization or bridging by polymers are monitored by turbidimetry. Static and kinetic coefficients of friction are measured by ASTM methods using an Instron Tensile Tester. The size distribution of polystyrene particles is examined with a Coulter Counter. A scanning tunneling microscope is used to study surface topography of gold and graphite coatings.
combined to present a more complete characterization. Multiple interactions, nonideal conditions, inhomogeneity, and experimental limitations present the students with “real-world” deviations from the theoretical ideal, giving them an appreciation of what research and technology development entails. Recently, an Advanced Characterization Laboratory course was developed using faculty expertise to provide graduate students with the opportunity to gain experience with techniques used in research laboratories to characterize complex fluids. A summary of the experiments offered in this course is provided in Table 3. Discussion Approximately 210 students have received the M.S. in CPS degree since it was first offered in 1974. Since 1978, 342 undergraduate chemical engineers have elected the four-course sequence, which comprises 10-25% of each chemical engineering graduating class at Carnegie Mellon. The graduates work
Table 2. Experimental Polymer Science Experiment Title Emulsion Polymerization
Mechanical Properties of Polymers
Adhesives Testing
Membrane Osmometry Static Light Scattering
Capillary Rheology
Gel Rheology Swelling and Elastic Modulus of Cross-linked Rubber
Thermal Analysis of Polymers
Injection Molding of Thermoplastic Polymers Dilute Solution Polymer Viscosity
Size Exclusion Chromatography (SEC)
Description Polyethylacrylate is synthesized by the free-radical polymerization of ethyl acrylate monomer in an emulsion system. Tensile properties of polymer films and elastomers are determined using ASTM methods with an Instron Tensile Tester. The appropriateness of adhesives in various applications is determined by ASTM methods using an Instron Tensile Tester. Polymer molecular weight is determined by osmotic pressure and solution thermodynamics. Zimm plots are used to calculate polymer weight-average molecular weight, chain dimensions, and polymer-solvent interactions in dilute solution. Capillary extrusion rheometer data are used to study melt properties of polymers and to calculate melt viscosity, the non-Newtonian flow index, and wall shear rates. A cone-and-plate viscometer is used to study flow properties of dilute dispersions. The solvent swelling behavior and elongation under load of vulcanized rubber are measured and used to characterize cross-linking. A differential scanning calorimeter is used to study thermal events in polymer samples. A laboratory mixing molder is used to mold polymer specimens for tensile testing. The viscosities of dilute polymer solutions are measured using a capillary viscometer. The polymer molecular weight is then determined with the Mark-Houwink equation. SEC data are evaluated to determine number- and weight-average molecular weights.
in industries that manufacture, for example, coatings, paints, pigments, surfactants, nanomaterials, polymers, food, personal care products, cosmetics, and biomaterials. Student assessments of the CPS laboratory and lecture courses have been obtained from faculty course evaluations conducted by the university each semester. They are available from 1978 to 2007 for the laboratory courses and from 1988 to 2007 for the lecture courses. From the 30 years’ worth of data for the laboratory courses, we find that students enrolled in the laboratory courses rated the overall courses with an average value of 4.4 on a 5.0 scale, where 5.0 is the highest possible score of excellent. The data represent responses from 195 students of the 342 total students, which comprise 57% of all students taking the courses in the past 30 years, a clear demonstration of the usefulness of these courses from the student perspective. For the lecture courses, data from the period 1988-2007 show that the Physical Chemistry of Colloids and
2304 Ind. Eng. Chem. Res., Vol. 48, No. 5, 2009 Table 3. Experiments in the Advanced Characterization of Complex Fluids Experiment Title Advanced Rheology
Electrophoresis of Pigment Dispersions Dynamic Surface Tension by Bubble Pressure Method Dynamic Contact Angle by Tilted Plate Method
Atomic Force Microscopy (AFM)
Dynamic Light Scattering (DLS)
Surface Excess Concentration of Adsorbed Species by Ellipsometry Streaming Potential of Solid Surfaces
Description A research rheometer is used to identify non-Newtonian flow behavior and measure viscoelasticity. Zeta potentials of pigment dispersions are calculated from particle mobility in an electric field. A bubble pressure tensiometer is used to study surfactant activity as a function of surface age. Advancing and receding angles of a moving contact line are measured and used to construct Zisman plots and determine the critical wettability of surfaces. An atomic force microscope in imaging mode is used to study nanoscale defects, phase separation, and crystal structure. DLS is used to measure the diffusion coefficients of colloidal dispersions and polymer solutions, which, in turn, provides information about the hydrodynamic size of the particles/coils. An ellipsometer is used to measure the amount of adsorbed surfactant on a surface. A rotating disk apparatus is used to measure the streaming potential and calculate the zeta potential of the solid surface.
Surfaces course rating was 4.2/5.0, with 87% of the 476 students responding to the course evaluation; for the Physical Chemistry of Macromolecules course, the overall score was 4.1/5.0, with 82% of students responding. Note that the course evaluations are not mandatory; students are encouraged to provide a response, but there is no method for ensuring that each student evaluates the course. From surveys, graduates of the program cited workplace advantages they attribute to their participation in the CPS Program. They feel that they are on an equal level with more experienced employees, which makes adjustment on the job easier because they can take on duties more efficiently and become effective employees sooner. They are confident in their ability to interpret data and solve problems using concepts and techniques learned in the program. Graduates reported being more comfortable during the job interview process, especially when discussing technical topics with prospective employers. CPS also provides exposure to a valuable technical vocabulary that is industrially relevant. We continue to receive similar comments from today’s recent alumni, confirming the importance and relevance of their exposure to the topics presented in the CPS program and the very positive and significant effect the experience has had on their careers.
Industrial scientists and engineers familiar with the program were polled in 1998 regarding their opinion of the CPS Program. This group included CPS Advisory Board members and alumni from industrial corporations. Both groups had hired students from our program. Their comments echoed those of the graduates mentioned previously. They concluded that the CPS Program fills an educational gap and that its graduates are better prepared to handle challenges and to compete and contribute on the job immediately. Comments such as these have also been made by alumni who return to our campus on a regular basis to recruit new graduates; they often specifically express interest in interviewing prospective graduates with a CPS background. Summary The CPS Program exemplifies how industry and the research university can combine to form novel programs that enhance education in engineering. As applications for nanomaterials and macromolecules continue to grow, 37 years after the program’s inception, we observe that CPS courses for both graduate and undergraduate students at Carnegie Mellon are elected by a continually more diverse group of students that come from the Departments of Chemical Engineering, Chemistry, Physics, Civil & Environmental Engineering, Materials Science and Engineering, Biomedical Engineering, and Mechanical Engineering. This clearly demonstrates the continued importance of these multidisciplinary topics to many areas of science and technology. Acknowledgment Writings of the late Ethel Zaiser Casassa, Emerita Professor of Chemical Engineering, CPS Program Director, 1981-1988, and CPS Laboratory, Founder and Director, 1972-1988, at Carnegie Mellon contributed to the historical facts and perspective for this article. Literature Cited (1) Lindenmeyer, P. H. Wake Up and Smell the Coffee! Chem. Eng. News 1974, 52 (Nov 18), 4. (2) Matijevic, E. ColloidssThe World of Neglected Dimensions. Chem. Technol. 1973, (Nov), 656. (3) Krieger, J. H. Colloids, polymers, surfaces emphasized. Chem. Eng. News 1974, 52 (Dec 23), 15. (4) Hiemenz, P. C., Rajagopalan, R. Principles of Colloid and Surface Chemistry, 3rd ed.; Marcel Dekker Inc.: New York, 1997. (5) Evans, D. F., Wennerstrom, H. The Colloidal Domain: Where Physics, Chemistry, Biology and Technology Meet; Advances in Interfacial Engineering; Wiley-VCH: New York, 1999. (6) Rosen, S. L. Fundamental Principles of Polymeric Materials, 2nd ed.; Society of Plastics Engineers Monographs; John Wiley & Sons: New York, 1993. (7) Coleman, M. M., Painter, P. C. Fundamentals of Polymer Science, 2nd ed.; CRC Press: Boca Raton, FL, 1998.
ReceiVed for reView April 1, 2008 ReVised manuscript receiVed August 5, 2008 Accepted August 7, 2008 IE8005148
