Related Experiment Video
Updated: Mar 31, 2026
06:54
Author Spotlight: Advances in Nanoscale Infrared Spectroscopy to Explore Multiphase Polymeric Systems
Published on: June 23, 2023
1.4K
Moving-window two-dimensional correlation infrared spectroscopic study on the dissolution process of poly(vinyl
Bai Xue1, Junhua Zhang2, Tao Zhou1
1State Key Laboratory of Polymer Materials Engineering of China, Polymer Research Institute, Sichuan University, Chengdu, 610065, China.
Analytical and Bioanalytical Chemistry
|October 16, 2015
Summary
Polyvinyl alcohol (PVA) dissolution involves water diffusion into amorphous and crystalline regions, changing with temperature. Hydrogen bonds break and reform, facilitating PVA
Area of Science:
- Polymer Science
- Materials Science
- Spectroscopy
Background:
- Polyvinyl alcohol (PVA) is a versatile polymer with applications in various industries.
- Understanding the dissolution behavior of PVA is crucial for optimizing its processing and applications.
- Previous studies have suggested specific spectral features indicate PVA crystallinity.
Purpose of the Study:
- To investigate the dissolution process of fully hydrolyzed polyvinyl alcohol (PVA).
- To elucidate the role of water diffusion and hydrogen bonding during PVA dissolution.
- To re-evaluate spectral indicators of PVA crystallinity in solution.
Main Methods:
- Temperature-dependent Fourier transform infrared spectroscopy (FTIR).
- Moving-window two-dimensional (MW2D) correlation infrared spectroscopy (IR).
- Analysis of OH stretching and bending regions, and a peak at 1141 cm⁻¹.
Main Results:
- FTIR spectra showed abundant water, impacting OH stretching and bending regions.
- Water diffusion into amorphous regions occurred below 45°C, and into crystalline regions above 45°C.
- The 1141 cm⁻¹ peak's behavior contradicted its role as a sole indicator of crystallinity in solution.
- Hydrogen bonds within PVA were broken and reformed with water molecules during dissolution.
- MW2D correlation analysis revealed hydroxyl group movements, with increased range and intensity in solution compared to solid state.
Conclusions:
- PVA dissolution is a complex process involving temperature-dependent water diffusion into different regions.
- The spectral characteristics of PVA in solution are significantly influenced by water interactions.
- The peak at 1141 cm⁻¹ is not a reliable indicator of PVA crystallinity in aqueous solutions.
Related Concept Videos
01:28IR and UV–Vis Spectroscopy of Carboxylic Acids
6.2K
In IR spectroscopy of carboxylic acids, the C=O bond shows a characteristic band between 1710 and 1760 cm⁻¹, and the O–H bond exhibits a broad band between 2500 and 3300 cm⁻¹.
However, the stretching absorptions for the C=O bond vary depending on the structure of carboxylic acids. The C=O bond of the free carboxylic acids shows a higher stretching frequency, 1760 cm−1, while H-bonded carboxylic acids (dimers) exhibit stretching absorptions at a lower frequency,...
However, the stretching absorptions for the C=O bond vary depending on the structure of carboxylic acids. The C=O bond of the free carboxylic acids shows a higher stretching frequency, 1760 cm−1, while H-bonded carboxylic acids (dimers) exhibit stretching absorptions at a lower frequency,...
6.2K
01:16IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
3.7K
A covalently bonded heteronuclear diatomic molecule can be modeled as two vibrating masses connected by a spring. The vibrational frequency of the bond can be expressed using an equation derived from Hooke's law, which describes how the force applied to stretch or compress a spring is proportional to the displacement of the spring. In this case, the atoms behave like masses, and the bond acts like a spring.
According to Hooke's law, the vibrational frequency is directly proportional to...
According to Hooke's law, the vibrational frequency is directly proportional to...
3.7K
01:29IR and UV–Vis Spectroscopy of Aldehydes and Ketones
7.9K
Infrared spectroscopy, also known as vibrational spectroscopy, is mainly used to determine the types of bonds and functional groups in molecules. In aldehydes and ketones, the carbonyl (C=O) bond shows an absorption around 1710 cm-1. The C=O bond vibration of an aldehyde occurs at lower frequencies than that of a ketone. In addition to the C=O absorption in an aldehyde, the aldehydic C–H bond also gives two peaks in the 2700–2800 cm-1 range. This absorption, coupled with the...
7.9K
01:15Theories of Dissolution: Diffusion Layer Model
2.2K
Dissolution, the process by which drug particles dissolve in a solvent, is explained by the diffusion layer model, a theoretical framework that simulates the absorption of oral drugs and allows us to analyze experimental data.
This process starts with a thin layer, saturated with the drug, forming at the interface between the solid and liquid. The solute then diffuses from this layer into the main solution. The Noyes-Whitney equation suggests that the rate of dissolution relies on the diffusion...
This process starts with a thin layer, saturated with the drug, forming at the interface between the solid and liquid. The solute then diffuses from this layer into the main solution. The Noyes-Whitney equation suggests that the rate of dissolution relies on the diffusion...
2.2K
01:24IR Spectroscopy: Molecular Vibration Overview
6.2K
When Infrared (IR) radiation passes through a covalently bonded molecule, the bonds transition from lower to higher vibrational levels. The fundamental vibrational motions that result in infrared absorption can be classified as stretching or bending vibrations.
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
6.2K
01:29UV–Vis Spectroscopy: Woodward–Fieser Rules
29.6K
UV–Visible absorption spectra of conjugated dienes arise from the lowest energy π → π* transitions. The light-absorbing part of the molecule is called the chromophore, and the substituents directly attached to the chromophore are called auxochromes. A strong correlation exists between the absorption maxima, λmax, and the structure of a conjugated π system. The Woodward–Fieser rules predict the value of λmax for a given structure by adding the...
29.6K