Wonsik Shin , Joung Sook Hong , Dae Yeon Kim , Si Yoon Kim , Kyu Hyun , Jun Dong Park , Kyung Hyun Ahn
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引用次数: 0
Abstract
This study investigates the effect of cellulose nanocrystals (CNCs) to Pickering emulsions prepared with microalgal particles (Spirulina sp. (SPI), Chlorella sp. HS2 (CLO)). The microalgae particles show a weak interfacial localization and Pickering behavior on the O/W emulsion depending on the size (avg. drop size ∼5.39 μm with SPI and 22.15 μm with CLO), resulting in a different stabilization effect. When CNC is additionally mixed with the Pickering emulsions including large microalgae particles (CLO), CNC replaces microalgae particles and localizes at the interface, enhancing strong emulsion stabilization. For the Pickering emulsions including small microalgae (SPI), CNC localizes at the continuous phase, forming a network structure regardless of the concentration. This interfacial localization behavior of CNC against microalgae particles is reflected in the rheological behavior of the Pickering emulsion. Depending on the location of CNC, the emulsions exhibit the two-step yielding behavior, mainly attributed to the CNC network in the continuous phase. The complex role of particles in the emulsion system is more sensitively reflected in the large amplitude oscillatory shear (LAOS) region, characterized using the sequence of physical process (SPP) rheological analysis. The maximum elasticity (Emax) in SPP analysis, which indicates the recovery of the deformed structure, exhibits a significant difference, discriminating structural characteristics of CNC dispersion incorporated with microalgae particles. Emulsion with CLO-CNC has lower Emax than the SPI-CNC case because CNC particles disperse at the interface and the continuous phase. Then the distance between CNC particles is longer, resulting in a weak network structure throughout the emulsion. Due to a weak network of CNC, the emulsion is more vulnerable to coalescence compared to the SPI-CNC system. Therefore, this study suggests that CNC particles added to the Pickering emulsion with microalgae compete to localize at the interface and give coalescence suppression effects to the emulsion. Also, for the Pickering emulsion system composed of multi-particles, rheological analysis including SPP analysis successfully indicates structural characteristics and flow-induced stabilization of Pickering emulsions with multi-particles that microscopic characterization could not detect.
期刊介绍:
Algal Research is an international phycology journal covering all areas of emerging technologies in algae biology, biomass production, cultivation, harvesting, extraction, bioproducts, biorefinery, engineering, and econometrics. Algae is defined to include cyanobacteria, microalgae, and protists and symbionts of interest in biotechnology. The journal publishes original research and reviews for the following scope: algal biology, including but not exclusive to: phylogeny, biodiversity, molecular traits, metabolic regulation, and genetic engineering, algal cultivation, e.g. phototrophic systems, heterotrophic systems, and mixotrophic systems, algal harvesting and extraction systems, biotechnology to convert algal biomass and components into biofuels and bioproducts, e.g., nutraceuticals, pharmaceuticals, animal feed, plastics, etc. algal products and their economic assessment