Microwave synthesized and laser activated hyaluronic/polyacrylate/basil seed cloud seeding glaciogenic/hygroscopic nanocomposite

Abstract

Cloud seeding is a technique used for weather modification, but the commonly used material, silver iodide, has environmental concerns. In response to this concern, we report a biocompatible hyaluronate/polyacrylate/basil seed nanocomposite was synthesized in this study using microwave irradiation and chemical esterification. A new approach involving polarized CO₂ laser ablation was developed to enhance the nanocomposite's active surface area. The study focused on investigating changes in morphology and surface area during irradiation, which are crucial for effective cloud seeding while minimizing environmental impact. Thermogravimetric analysis showed acceptable water adsorption/absorption properties of up to 98.55%. with this feature, the synthesized nanostructure displayed hygroscopic properties. Also, these amorphous nanocomposites exhibited pseudo-stacking disorder properties in their X-ray diffraction patterns making them a promising cloud seeding agent with glaciogenic properties. In the present study, after investigating nanocomposites, C5 sample with 5 min microwave radiation and one-minute pulse between each radiation, was chosen as the best among the samples. Evaluation in a calibrated cloud seeding chamber revealed the nanocomposite's reliability, producing up to 1.18 (± 0.11) × 10¹⁴ particles of active cloud seeding compound per gram within a 45-minute timeframe. These results were observed at temperatures between - 14 and - 16 °C with a relative humidity exceeding 90%.

Keywords: Biocompatible nanocomposite; Cloud seeding; Glaciogenic and hygroscopic seeding; Pseudo stacking disorder; Secondary structure; Water absorption.

Fig. 1

(A) hyaluronic acid spectrum; (B) polyacrylic acid spectrum; (C) basil seed spectrum; (D) physical mixture of three raw precursors spectrum, (E) nanocomposite spectrum in optimum condition; (F) composite spectrum after long microwave irradiation (9 min).

Fig. 2

X-ray diffraction patterns of nanocomposites.

Fig. 3

TEM image of C5 sample (A) before exposure on the laser radiation (B) after exposure to the continuous wave of laser (C) after exposure to the pulsed laser (500 nm) (D) after exposure to the pulsed laser (100 nm); TEM image of C9 sample (E) before exposure on the laser radiation (F) after exposure to the continuous wave of laser (G) after exposure to the pulsed laser (500 nm) (H) after exposure to the pulsed laser (100 nm).

Fig. 4

H₂O adsorption/absorption of all samples over time.

Fig. 5

N₂ adsorption-desorption isotherms of all samples.

Fig. 6

Thermogravimetric analysis of all samples.

Fig. 7

Circular Dichroism spectra of (A) C5 sample before (b-C5) and after (a-C5) microwave and laser irradiation and (B) C9 sample before (b-C9) and after (a-C9) irradiation, and (C-i) physical mixture (mixture of raw materials without irradiation), (C-ii) one pulse microwave radiation (2 min), (C-iii) two pulse microwave radiation (1 + 1 min).