Abstract

In this work attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy was used to probe the thermal gelation behavior of aqueous solutions of hydroxypropyl methylcellulose (HPMC), specifically thermal gelation and accompanying precipitation. Cloud point measurements are usually evaluated through turbidity in dilute solutions but the method cannot readily be applied to more concentrated or highly viscous solutions. From the ATR-FTIR data, intensity changes of the ν(CO) band marked the onset of gelation and information about the temperature of gelation and the effect of the gel structure on the water hydrogen bonding network was elucidated. Changes in the relative intensities of bands associated with the methoxyl groups and hydrogen-bond-forming secondary alcohol groups indicated that hydrophobic polymer chain interactions were involved in the gelation process. The dominance of inter-molecular H bonding over intra-molecular H bonding within the cellulose ether in solution was also observed. The ATR-FTIR data was in good agreement with measurements of turbidity conducted on the same systems. The work indicates significant potential for the use of ATR-FTIR for the investigation of gelation and cloud point measurements in viscous cellulosic formulations.

Use of attenuated total reflectance Fourier transform infrared spectroscopy to monitor the development of lipid aggregate structures

Mateo R. Hernandez, Elyse N. Towns, Terry C. Ng, Brian C. Walsh, Richard Osibanjo, Atul N. Parikh, and Donald P. Land
Appl. Opt. 51(15) 2842-2846 (2012)

Chemical visualization of individual chondrocytes in articular cartilage by attenuated-total-reflection Fourier Transform Infrared Microimaging

Jianhua Yin and Yang Xia
Biomed. Opt. Express 2(4) 937-945 (2011)

Whispering gallery mode resonator sensor for in situ measurements of hydrogel gelation

Steven H. Huang, Saahil Sheth, Era Jain, Xuefeng Jiang, Silviya P. Zustiak, and Lan Yang
Opt. Express 26(1) 51-62 (2018)

Attenuated total reflectance spectroscopy with chirped-pulse upconversion

Hideto Shirai, Constance Duchesne, Yuji Furutani, and Takao Fuji
Opt. Express 22(24) 29611-29616 (2014)

Refractive indices of powdered materials using attenuated total reflectance spectroscopy

James B. Gillespie and George H. Goedecke
Appl. Opt. 28(18) 3985-3992 (1989)