Self-Assembly of Hydrophobic and Self-Healing Bio-nanocomposite-Coated Controlled Release Fertilizer

• Published in: ACS applied materials & interfaces
• Main Authors: Zhang, Shugang, Yang, Yuechao, Tong, Zhaohui, Gao, Bin, Gao, Ni, Shen, Tianlin, Wan, Yongshan, Yu, Zhen, Liu, Lu, Ma, Xiaoxiao, Guo, Yanle, Fugice, Job, Li, Yuncong C
• Format: Journal Article
• Language: English
• Published: United States 28.05.2020

Self-healing materials have received increased attentions due to their automatic detecting and repairing damage function. In this paper, a novel self-assembly and self-healing bio-nanocomposite was developed as a coating material for controlled release fertilizer. This nanotechnology-enabled coating is environmentally friendly, highly efficient, and possesses tunable nutrient-releasing characteristic. In the synthesis process, bio-based polyurethane coated urea (BPCU) was prepared by the reaction of bio-polyols with isocyanate. The BPCU were then modified by layer-by-layer technology to prepare self-assembling modified bio-based polyurethane coated urea (SBPCU). Lastly, hollow nano-silica (HNS) particles loaded with the sodium alginate (SA) was used to modify SBPCU to fabricate of self-assembling and self-healing bio-based polyurethane coated urea (SSBPCU). The results show that the self-assembled materials were synthesized through electrostatic adsorption. The self-healing was observed through the scanning electron microscope (SEM) and 3D-X-ray computed tomography, revealing the mechanism was that the repair agent released from HNS and reacted with curing agent to block the pore channels and cracks of the coating. As a result, the SSBPCU exhibited the highest hydrophobicity and surface roughness, thus the slowest release rate. For the first time, this work designs a novel strategy to solve the bottleneck problem that restricts the development of controlled release fertilizer.