Paper Number
TM13                         My Program 

Session
Techniques and Methods

Title
Dynamic diffusive interfacial transport (D-DIT): Tracking water concentration with short-wave IR (SWIR)

Presentation Date and Time
October 16, 2024 (Wednesday) 4:05

Track / Room
Track 7 / Room 502

Authors (Click on name to view author profile)

  1. Kelkar, Parth U. (Purdue University, School of Materials Engineering)
  2. Erk, Kendra A. (Purdue University, School of Materials Engineering)
  3. Lindberg, Seth (Procter & Gamble Co.)

Author and Affiliation Lines (in printed abstract book)
Parth U. Kelkar1, Kendra A. Erk1 and Seth Lindberg2
1School of Materials Engineering, Purdue University, West Lafayette, IN 47906; 2Procter & Gamble Co., West Chester, OH 45069

Speaker / Presenter 
Lindberg, Seth

Keywords
experimental methods; methods; surfactants; techniques

Text of Abstract
SWIR imaging technology has been used extensively in defense applications and has more recently also found use in machine-vision inspection of silicon wafers and agricultural products. Water molecules absorbs well ~1400nm, causing objects with high moisture content to appear black. Surfactants and other molecules commonly encountered in consumer products do not absorb the same enabling good contrast. Combining short-wave infrared (SWIR) imaging with cross-polarized visible imaging enables high-resolution, high-throughput, and in-situ identification of liquid crystalline phases and water compositions. D-DIT can be used to study time-dependent material relationships across a diverse range of materials and processes such as phase evolution and dissolution of concentrated surfactants surfactant droplets and drying of aqueous polymer films (Kelkar et al., Review of Scientific Instruments, 2024). In this study, the dynamic phase evolution of a binary aqueous solution of a non-ionic surfactant hexaethylene glycol monododecyl ether (C12E6) is presented. Phase transitions in confined environments were found to differ from equilibrium phase behavior and the micellar to hexagonal phase transition concentration (C*) depended on the ratio of water to surfactant. The effects of industrially relevant additives such as monovalent common salt and propylene glycol on the dissolution of lamellar-structured sodium lauryl ether sulfate pastes were also studied. This instrument was also used to study the inverse hydration: the drying kinetics of aqueous poly(vinyl) alcohol films. Directly tracking water helped draw meaningful correlations between the viscosity and drying time of aqueous films. Dynamic-DIT has already generated previously inaccessible data for surfactant phase transitions and has the potential to become a turnkey method for several other studies such as dissolution and drying.