Dynamic Light Scattering, Interfacial Properties, and Conformational Analysis of Biodegradable Quarternary Ammonium Surfactants

Abstract

Aggregation properties of biodegradable ammonium surfactants containing amide and ester groups in the bulk and at the air-water interface were investigated as a function of surfactant tail length m using dynamic light scattering and surface tension experimental methods. The results indicate that surfactants containing an ester group in the structure display higher aggregation ability in the volume and form more densely packed layer of molecules at the air-water interface than those with an amide group. The results of physical measurements were correlated with 3D models of respective surfactant molecules. As the results indicate, a surfactant molecule headgroup containing an ester group shows higher flexibility than that with an amide group in its structure, which is documented by somewhat smaller headgroup size and denser packing at the air-water interface.

Biodegradable gemini surfactants. Correlation of area per surfactant molecule with surfactant structure

“…Polymethylene spacer d2e containing two ester groups is even more flexible as results from the area per surfactant molecule curve lying below both area curves for surfactant molecules with the spacers containing amide groups. This generally corresponds with our previous experimental findings supported by the computer model of surfactant molecules containing ester and amide group that the spacer with the ester group is somewhat shorter and more conformationally flexible than that with the amide group which results in denser packing of surfactant molecules at the air-water interface [15].…”

“…In our previous study [15], we have found that the biodegradable ester group in a surfactant molecule structure is more flexible than an amide group. This results in a smaller area per surfactant molecule values at the air-water interface as well as corresponds with a shorter chain length calculated from the respective computer model of the surfactant molecule.…”

“…For the sake of comparison, two analogical single chain surfactants with a cyclohexane group replaced by a phenyl ring are taken from our previous results [15]. They are denoted as m2ab and m2eb.…”

“…The goal of the present study is to extend our previous research on gemini ammonium surfactants and some single chain ammonium surfactants at the air/water interface [14,15] by single chain and gemini surfactants with biodegradable chemical groups and to correlate the chemical architecture of surfactant molecule with its behavior at the air/water interface.…”

Synthesis and Properties of Biodegradable and Chemically Recyclable Cationic Surfactants Containing Carbonate Linkages

“…Therefore, the development of surfactants with an improved biodegradability and recyclability using renewable resources by an environmentally benign process is now needed with respect to the establishment of a green and sustainable chemistry. Biodegradable and cleavable surfactants, such as amino acid-based, sugar-based and ester containing surfactants, have so far been synthesized [4][5][6][7][8] .…”