CPS Labs

Soft Materials - characterization tools?

Colloidal and macromolecular specifies are often processed or used in solution. Tools to characterize the structure and dynamics of these species in solution are vital to the ability to design and develop soft materials. The CPS Labs at Carnegie Mellon offer access to a wide range of important characterization tools. The two courses allow students to spend time learning how to design experiments, process data, and troubleshoot issues. The courses are divided into a "Polymers" and a "Colloids" part out of tradition even though many of the techniques are relevant to both fields. Each lab has a theme that is motivated by real scientific and engineering problems faced by soft materials industries, these themes help students put the need for the data and techniques in context.

Structure of the course

In S23, the labs are being offered as two mini courses. 06-801 focuses on polymers and will be the focus of the first half of S23. 06-802 focuses on colloids and will be the focus of the second half of the semester. Students should register for 3 units for each mini and are expected to commit 6 hrs a week to the course - lab sessions will be scheduled for twice a week (1.5 - 2 hr per session); we will work with teams to find times that work for all team members - there is some flexibility but the schedule for the half semester will be planned during the first week. The courses are not connected and students should take one or both depending on their interests and needs. Students will work in teams which will be a mix of students from different degree programs and disciplines. If the current scheduled time is a conflict, this is not a problem - please reach out to the instructor for assistance and options!

Time commitment for course: 6 hours per week (3-4 hr in lab broken into 2 sessions and 2-3 hours of data analysis) - week 1 of each mini will be organizational leaving 6 weeks (2 weeks per experiment) for the content of the course. Each experiment will require a lab report, the course will be graded based on activity in the lab and the reports.

06-801: Polymers and Macromolecules in Solution

Building on topics discussed in lecture courses, this course focuses on characterization of the solution properties of macromolecules. The theme of the current lab is driven by the goal of incorporating green solvents in the processing and recycling of synthetic polymers. Replacement of current solvents (aromatics and alkanes derived from fossil fuels) is driven by a number of forces, and success will require determination of the basic properties of polymers in these new solvents. The focus on the S23 lab session will follow on the last few sessions of the lab and we will characterize polystyrene properties in the terpene d-limonene which is extracted from citrus waste.

The three techniques covered will be:

Ubbeholde viscometry - intrinsic viscosity, Mark-Houwink parameters
Static Light Scattering - Mw, virial coefficients, Radius of gyration
Rotational rheometry - Zero-shear viscosity, linear rheology

06-802: Colloids and Surfaces

Building on topics discussed in lecture courses, this course focuses on characterization of the dispersion and self-assembly properties of colloids. The theme of the current lab is driven by the goal of efficient formulation of multicomponent systems. Replacement of individual molecules in a complex formulation is driven by a number of forces and a formulation scientist needs to know how changing one component in a formulation will impact overall behavior. The focus on the S23 lab session will follow on the last few sessions of the lab and we will characterize binary mixtures of surfactants and colloids.

The three techniques covered will be:

Dye solubilization - cmc, solubilization power
Dynamic light scattering - diffusivity, size
Pendant Drop Tensiometry - interfacial tension, cmc

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