Microcapsules with compact wall from hydrocarbon/fluorocarbon composite surfactants for electrophoretic display

Abstract

The components and their concentration ratio of surfactant mixture in aqueous solution of gelatin and sodium carboxymethylcellulose (NaCMC) are very important during the preparation of stable microcapsules for electrophoretic display. In this work, hydrocarbon/fluorocarbon composite surfactant was introduced for the first time into the capsule wall to improve the chemical resistance and barrier property of the microcapsules. By investigating surface tension and zeta potential of NaCMC with the mixture of sodium dodecyl sulfate (SDS)/perfluoro-nonene oxy benzene sulfonate (OBS), we found that both the presence of hydrophobic interaction and the hydrogen bonding between NaCMC and SDS/OBS enhanced the adsorption of NaCMC at the oil/water interface and thus facilitated the formation of capsule wall. The morphology, particle size, surface free energy and thermal stability of the obtained microcapsules were characterized. The results showed that optically transparent microcapsules with uniform size, smooth surface and compact wall can be obtained by adjusting the pH value of the reaction system and the concentration ratio of SDS/OBS. Based on the prepared microcapsules, a matrix display prototype operated at 9 V direct current in static driven mode was fabricated. microcapsules, compact wall, sodium carboxymethylcellulose, sodium dodecyl sulfate/perfluoro-nonene oxy benzene sulfonate composite surfactant, electrophoretic display

A review of the preparation and application of flavour and essential oils microcapsules based on complex coacervation technology

“…The addition of surfactant was recognised to increase the interaction between GE and CMC, thereby facilitating the progress of complex coacervation. A series of experiments performed by Li et al and Dai and co‐workers used GE–CMC for the preparation of microcapsules by complex coacervation. The surfactant sodium dodecyl sulfate was found to enhance the adsorption amount of CMC on the oil–water interface and to interact with CMC by hydrophobic interaction.…”

Microcapsule-based materials for electrophoretic displays

“…As the addition of acetic acid solution in the system, when the pH value is 4.5, gelatin and NaCMC-SDS/OBS with oppositely charges occurred complex coacervation reaction due to charge neutralization. Most of complex coacervates in colloid phase gathered on the surface of core materials to form complex coacervation layer, which formed compact microcapsules after being cross-linked by glutaraldehyde [41]. Figure 9a displays the whole appearance of single GE-NaCMC-0.5mM SDS/ 0.2mM OBS microcapsule, which has smooth surface and perfect spherical shape.…”

“…When microcapsules are put on the vacuum spraying gold film, they extrude each other and change from spherical to pentagonal or hexagonal shape due to the good elasticity of the capsule wall as shown in Figure 9b. The degradation temperature of gelatin-based microcapsules is much higher than the boiling temperature of TCE (394.15 K), demonstrating high thermal stability of gelatin-based microcapsules [34,[41][42][43][44]. Figure 10 shows the weight loss of microcapsules as a function of annealing time at 395.15 K. The weight loss is mostly attributed to the thermal release of the core material of TCE.…”