Layer-by-layer deposition of clay and a polycation to control diffusive release from polyurea microcapsules

Hickey, Janice N.; Burke, Nicholas A. D.; Stöver, Harald D. H.

doi:10.1016/j.memsci.2010.11.047

Cited by 28 publications

(16 citation statements)

References 37 publications

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“…These materials include polymers (Kumar et al 2014;Paradelo et al 2014;Chowdhury 2014), silica (Qian et al 2013;Wanyika 2013;Zhang et al 2014b), polyphosphates (Cini et al 2012), waxes (Rodrigues et al 2014), clay/organo-clay (Hickey et al 2011;Sahoo et al 2014), agro wastes (Petruccioli et al 2011). However, the materials used to prepare release systems should satisfy the some requirements related to the diffusion/solubility/degradation/fabrications.…”

Section: Controlled-release Agrochemical Delivery Systems and Their Amentioning

confidence: 99%

Polysaccharides as safer release systems for agrochemicals

Campos

Oliveira

Fraceto

et al. 2014

Agron. Sustain. Dev.

281

175

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Agrochemicals are used to improve the production of crops. Conventional formulations of agrochemicals can contaminate the environment, in particular in the case of intensive cropping. Hence, there is a need for controlledrelease formulations of agrochemicals such as polysaccharides to reduce pollution and health hazards. Natural polysaccharides are hydrophilic, biodegradable polymers. This article reviews the use of polysaccharides in the form of micro-and nanoparticles, beads and hydrogels. The main points are: (1) slow release formulations minimize environmental impact by reducing agrochemical leaching, volatilization and degradation. For example, 50 % of the encapsulated insecticide chlorpyrifos is released in 5 days, whereas free chlorpyrifos is released in 1 day. (2) Slow release formulations increase the water-holding capacity of soil. (3) Slow release formulations better control weeds in the long run. (4) Polymer-clay formulations store ionic plant nutrients. (5) Polymer hydrogel formulations reduce compaction, erosion, and water run-off. They increase soil permeability and aeration, infiltration rates, and microbial activity, and, in turn, plant performance. In conclusion, polysaccharide formulations can be used for safer use of agrochemicals.

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Section: Controlled-release Agrochemical Delivery Systems and Their Amentioning

confidence: 99%

Polysaccharides as safer release systems for agrochemicals

Campos

Oliveira

Fraceto

et al. 2014

Agron. Sustain. Dev.

281

175

View full text Add to dashboard Cite

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“…Polymer/clay nanocomposites (PCN) have been widely investigated in recent decades towards preparation methods and determining the associated improvements in a broad range of applications . Common strategies to obtain nanocomposite morphologies involve but are not limited to one or a combination of the following routes: adding polar functional groups through reactive melt processing , using quaternary ammonium salts as coupling agents , in‐situ polymerization, , latex coagulation , and layer‐by‐layer (LBL) assembly of polyelectrolytes . The majority of the relevant literature nowadays tends to exhibit a ubiquitous understanding that a promising level of intercalation and exfoliation can be achieved with attractive polymer‐clay interactions, whereas microcomposite‐like aggregation is broadly observed with weak associations between clay galleries and molecular chains.…”

Section: Introductionmentioning

confidence: 99%

Structure, nanomechanics, and dynamics of dispersed surfactant‐free clay nanocomposite films

Zhang

Zhao

Snyder

et al. 2018

Polymer Engineering & Sci

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The current work presents a new approach to achieve high quality dispersion of surfactant‐free nanoclay tactoid particles in sub‐micron thin films despite the absence of organic modifier. Natural Montmorillonite particles, Na+ Cloisite, were dispersed in thin films of polycaprolactone (PCL) through a flow coating technique assisted by ultra‐sonication. Wide‐angle X‐ray scattering (WAXS), grazing‐incidence wide‐angle X‐ray scattering (GI‐WAXS), and transmission electron microscopy (TEM) were used to confirm the level of natural clay dispersion down to the level of tactoids (sub‐micron scale stacks of clay sheets). These characterization techniques were carried out in conjunction with an analysis of nanomechanical properties via strain‐induced buckling instability for modulus measurements (SIEBIMM), a high‐throughput technique to characterize thin film mechanical properties. The buckling patterns indicate that the natural clay tactoids separate buckling‐enhancing (high‐modulus) crystalline regions and interconnect buckling‐suppressing amorphous (low‐modulus) regions. Due to the tactoid length scale, the glass transition behavior of the composites as characterized by broadband dielectric relaxation spectroscopy was unmodified by the clay. Likewise, the glass transition temperature, Tg, and fragility (slope of relaxation time behavior approaching Tg), remain unaffected, indicating that these dispersed tactoids do not induce pronounced confinement effects on dynamics. POLYM. ENG. SCI., 58:1285–1295, 2018. © 2018 Society of Plastics Engineers

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“…The preparation technology is convenient as molecular assembly can be completed on particle surface through simple alternating dip coating (17,18). At the same time, it can be assembled in aqueous solution at normal temperature.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Research of Butylene Fipronil Microencapsulation by Layer-by-Layer Polyelectrolyte Self-Assembly

Liao

Liu

et al. 2015

Journal of Macromolecular Science, Part A

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This paper introduced the preparation of butylene fipronil-loaded microcapsules with oppositely charged chitosan and sodium lignosulfonate as shell materials. It summed up the performance, preparation methods of microcapsules and sketched the application status of layer-by-layer self-assembly. The whole progress of the preparation was controlled by measuring the change of the Zeta potential and the morphology of microcapsules was characterized by microscope and SEM. Entrapment efficiency and slow release performance of the microcapsule were determined as measurement index. The results of experiment showed that the surface of the microcapsules was rougher than the butylene fipronil particles. With the increasing layer number of assembly, the entrapment efficiency reduced while the slow release performance increased. After encapsulation, the photodegradation rate of butylene fipronil under the UV decreased obviously. Results showed that the condition of preparation was the best when NaCl with the concentration of 0.5 mol/L and PH of 5.0.

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Layer-by-layer deposition of clay and a polycation to control diffusive release from polyurea microcapsules

Cited by 28 publications

References 37 publications

Polysaccharides as safer release systems for agrochemicals

Polysaccharides as safer release systems for agrochemicals

Structure, nanomechanics, and dynamics of dispersed surfactant‐free clay nanocomposite films

Preparation and Research of Butylene Fipronil Microencapsulation by Layer-by-Layer Polyelectrolyte Self-Assembly

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