Exploring Nanotechnology with Electrospinning: Design, Experiment, and Discover!

Nanotechnology is a challenging concept to teach. The length scales involved are difficult to visualize, the products are invisible to the human eye and in most cases the fabrication and characterization of nano-scale materials are prohibitively expensive for high school science programs. Moreover, the inaccessibility of nanotechnology in the classroom reduces the student’s experience to factual recall of a list of properties and advantages of materials at the nanometer scale. This situation does nothing to alleviate the perception that science/engineering is boring and does not engage students in the actual work patterns and discourse of practicing Science Technology Engineering and Mathematics (STEM) professionals. To redress this situation, students need not only to acquire the fundamental principles of nanotechnology, but participate in activities designed to encourage the habitus that will make it more likely they will pursue higher education in STEM fields. Electrospinning was chosen as a vehicle to explore nanofabrication because it is not only simple, but inexpensive. The physics, chemistry, and engineering principals used in electrospinning were attainable for high school students and the materials used to produce the nanofibers are safe for a classroom. In this project, the students built K’NEX electrospinning stations, and identified the process variables and material’s properties that control the resulting fiber diameters and product yield. They wrote a short proposal positing their hypothesis and a detailed experimental plan to optimize the fiber diameters and yield using their electrospinning station. The students implemented their experiment, trouble shot equipment failures, and collected their nanofibers. In collaboration with a local university their nanofibers were imaged using an SEM and the students analyzed the fiber diameter distributions with Image J software and a statistical package in Excel. The electrospinning activity was supported through a series of short lectures and inquirybased activities designed to provide a working knowledge of nanotechnology in general and the physics and chemistry employed in nanofiber production specifically. Additionally several modes of assessment were used through out the activity. In particular, an attitudes inventory was administered pre and post activity to evaluate change in perceptions about pursuing STEM careers. Summative assessments were used to gage student’s learning and performance based assessments were used to enhance student’s internalization of the subject matter. The students demonstrated an improved understanding of nanotechnology across the board and girls performed better than the boys on the summative assessment. As a capstone on the project the students produced posters to communicate their findings to their peers and compete in local and regional science fairs. This project was a joint effort between high school teachers who participated in the 2011 Research Experience for Teachers in Nanotechnology (RET-Nano), students in the 2011 Research Experience for Undergraduates (REU), their graduate mentors and faculty. The RET-Nano teachers and REU students/mentors worked together to develop lesson plans and activities to scaffold the high school student’s learning experience. The REU students P ge 25617.2 designed, built the tested the experimental hardware for the electrospinning traveling kit. And the graduate mentor travelled to all of the schools to demonstrate the electrospinning equipment and talk about her research. Introduction: Preparing the next generation of scientists and engineers for an increasingly global technology-based economy is a challenge faced by many STEM (Science, Technology, Engineering, and Mathematics) educators in the US. Although organizations such as the National Nanotechnology Initiative focus their efforts on preparing the nation for the estimated need for 2 million in the field of nanotechnology by 2015, many of our students are not measuring up 1 . For example, the National Assessment of Educational Progress (NAEP) reports that only 30% of eighth-graders and 21% of twelfth-graders ranked at or above the Proficient level in science. Similarly, only sixty-three percent of eighth-graders and 60% of twelfth-graders performed at or above the Basic level in science in 2009. Such reports clearly indicate that the US is quickly falling behind other world leaders in educating the next generation of scientists and engineers. Nanotechnology is the study of materials and their properties at the nanoscale, approximately sizes between 1 and 100 nanometers. At this scale, many materials exhibit properties and behaviors unique to the nanoscale. The applications of nanotechnology are becoming increasingly incorporated into modern life. For example, materials such as tennis rackets, makeup, and paint all utilize nanotechnology to make materials stronger, lighter and more energy efficient. Due to the high demand of a technical workforce versed in the area of nanotechnology, this field is becoming increasingly incorporated into the K-12 curriculum. While there is no doubt that the study and understanding of materials on the nanoscale is vital to the manufacturing preparedness of our country. For example, Cornell University in NY has established a “Nano World” traveling exhibit to educate students in the K-12 system about nanobiotechnology through engaging hands on activities 2 . Currently there had been an increased effort to incorporate hands – on activities in the science classroom through traveling kits such as the NISENET kits 3 . Research has shown that multi-modal approach not only addresses learning styles but scaffolds students learning to develop problem solving skills, inquiry based learning, and intellectual development 4 . Therefore a group of teachers in collaboration with Drexel University have developed a novel electrospinning lecture series and hands-on activity to be implemented into high school classrooms. The purpose of this project is three fold: 1) to encourage high school students to pursue careers in STEM fields 2) Introduce the field of nanotechnology and its applications to high school students 3) to provide a hands-on nanotechnology activity that involves the following elements: design, experimentation, analysis and reporting of results. This project was a joint effort between three high school teachers from the Greater Philadelphia Region (GPR) who participated in the 2011 NSF Research Experience for Teachers in Nanotechnology (RET-Nano), students in the 2011 NSF Research Experience for Undergraduates (REU), their graduate mentors and faculty. P ge 25617.3 Materials: Polyethelene Oxide (PEO) (MW: 300,000g/mol) was purchased from Sigma Aldrich and used as received. A VWR scale (Model: SLW302-US) was used to weigh dry PEO. All solutions were prepared with tap water mixed with a magnetic stir bar on a stir-plate in labeled 200 ml beakers. Solutions were contained in a small, rectangular reservoir for each setup. Various K’NEX pieces were provided and assembled to form a housing for the PEO reservoir and attachments for the K’NEX motor, axle, spindle holder and collection plate. (Appendix A) A high voltage power supply (Model: ES40P-10W/DAM) from Gamma HV Power Supplies was attached to custom breakout boxes built from electrical wall housings and wired to each female RCA plug in series on a face plate. Each electrospinning setup was connected to the breakout box via two RCA-Alligator cables; positive to the spindle wires, and ground to the collector plate. Electrical tape was used to insulate exposed connections. The K’NEX motors were powered by K’NEX battery packs containing two AA batteries. A collection plate of aluminum foil was wrapped around a 3X3 inch piece of copper screen attached to the common ground. Optionally, collection plates were visualized under classroom microscopes following each experiment to confirm the presence of polymer. Each foil collection plate was carefully placed into a plastic sandwich bag for transport to a local University and inspected under Scanning Electron Microscope (SEM). A Ziess VP 5 Supra scanning electron microscope (SEM) was used to image the fibrous mats. The SEM samples were prepared by sputter coating, Denton Vacuum, with Pt target at 40 milli amps for 35 s resulting in a 7-8 nm conductive film. The SEM was run at 3.5 KV at a 11mm working distance in high vacuum. Image results were sent via email to students for fiber diameter analysis with Image J. Methods: The schools that participated in this project were from three different regions in the Greater Philadelphia Region and reflect three different learning environments: An upperclassmen Physics course in a rural high school, two sophomore honors chemistry classes in an all male parochial school and two freshmen general science classes in an urban charter school. Reduced/free lunch data were not available from administration for these schools. All the teachers participated in a NSF RET-Nano summer program and the graduate student was a NSF REU Sensors mentor and the undergraduate was her NSF REU Sensors student. The RET-Nano teachers and REU students/mentors worked together to develop lesson plans and activities to scaffold the high school student’s learning experience. The REU student and mentor designed, built, and tested the experimental hardware for the electrospinning traveling kit shown in Figure 1 (a-d). And the graduate mentor travelled to all of school sites to demonstrate the electrospinning equipment and talk about her research. The electrospinning kit rotated to all three schools starting in the early fall with the physics class, then to the general science class finishing at the honors chemistry class. Page 25617.4 At each school the students were introduced to nanotechnology and its applications through a series of short lectures and inquiry-based activities designed to support the central c