Unraveling the droplet drying characteristics of crystallization‐prone mannitol – experiments and modeling

We investigate the interaction of an aqueous polymeric droplet with a tuneable continuous laser in an acoustically levitated environment. The effect of laser irradiation intensity and polymeric concentration on various spatio-temporal parameters is unearthed using high-speed shadowgraphy and theoretical scaling analysis. We observe four temporal phases: droplet evaporation, vapour bubble growth followed by membrane inflation, bubble/membrane rupture through hole nucleation and droplet breakup. During the initial droplet evaporation phase, concentration build-up at the droplet surface beyond a critical limit leads to the formation of a skin layer. It is revealed that, at a given location inside the droplet, hot spots occur, and the maximum temperature at the hot spots scales linearly with irradiation intensity until a bubble nucleates. The low-intensity laser interaction leads to symmetric membrane inflation that eventually forms holes at droplet poles and cracks on the shell surface. On the contrary, high intensity causes early bubble nucleation followed by asymmetric membrane inflation that eventually ruptures through multiple hole formation. Furthermore, the growth and rupture of the membrane is followed by a catastrophic breakup of the droplet. Two dominant atomization modes are reported at significantly high irradiation intensities: stable sheet collapse and unstable sheet breakup. The evolution of droplets into a stable/unstable sheet follows universally observed ligament and hole dynamics. A regime map is shown to describe the influence of polymer concentration and irradiation intensity on the strength and mode of droplet atomization.

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“…2014; Har et al. 2017), emulsion droplets (Mura et al. 2010) and nanoparticle-laden droplets (Pathak & Basu 2016 b ).…”

Section: Resultsmentioning

confidence: 99%

“…Aqueous polymeric solutions are one of the classes of multi-component solutions utilized in spray drying applications (Fu, Woo & Chen 2012;Har et al 2017). Polymeric droplets have a multitude of applications ranging from targeted drug delivery, thin films and coatings to surface patterning (Wilms 2005;Pathak & Basu 2016a;Zhu et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Bubble dynamics and atomization in evaporating polymeric droplets

et al. 2022

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“…Chen et al later reviewed the most important aspects of the modeling technique and compared it to the CDRC approach [ 109 ]. Har et al applied REA to glass filament single droplet drying of mannitol and found that the REA was sensitive to its temperature dependent crystallization behavior allowing for direct interpretation of drying profiles [ 140 ]. Putranto et al utilized REA to model the intermittent drying of mango tissues and kaolin for varying temperature and humidity by firstly deriving the relative activation energy from continuous convective drying [ 141 , 142 ].…”

Section: Physics Of Particle Formation From a Drying Dropletmentioning

confidence: 99%

Unraveling Particle Formation: From Single Droplet Drying to Spray Drying and Electrospraying

et al. 2020

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Spray drying and electrospraying are well-established drying processes that already have proven their value in the pharmaceutical field. However, there is currently still a lack of knowledge on the fundamentals of the particle formation process, thereby hampering fast and cost-effective particle engineering. To get a better understanding of how functional particles are formed with respect to process and formulation parameters, it is indispensable to offer a comprehensive overview of critical aspects of the droplet drying and particle formation process. This review therefore closely relates single droplet drying to pharmaceutical applications. Although excellent reviews exist of the different aspects, there is, to the best of our knowledge, no single review that describes all steps that one should consider when trying to engineer a certain type of particle morphology. The findings presented in this article have strengthened the predictive value of single droplet drying for pharmaceutical drying applications like spray drying and electrospraying. Continuous follow-up of the particle formation process in single droplet drying experiments hence allows optimization of manufacturing processes and particle engineering approaches and acceleration of process development.

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“…Therefore, simple yet effective methods of investigating single droplet drying kinetics, such as single droplet drying methods, are often applied. Amongst these techniques are optical levitation 10, electromagnetic levitation 11, 12, or suspending droplets via a thin wire or glass filament 13–17. Suspending a single droplet or particle in an ultrasonic levitator was implemented as a successful and well‐established experimental method to investigate the transport phenomena occurring on the surface of the droplet.…”

Section: Introductionmentioning

confidence: 99%

Spray Drying of Cellulose Nanofibers: Drying Kinetics Modeling of a Single Droplet and Particle Formation

Zaitone

Al-Zahrani

2021

Chem Eng & Technol

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Microparticles embedded with cellulose nanofibers (CNFs) are produced via spray drying. The microdroplets are created in the spray dryer by atomization. The solvent evaporates from the droplet, and the dried particles are formed. The drying kinetics on the scale of one droplet is still not well understood. Drying of a single droplet CNF suspension was investigated in an acoustic levitator. The drying kinetics and morphology evolution during the drying process were obtained. The reaction engineering approach (REA) model provided a reasonable prediction of the drying kinetics. An absolute relative error of 2.5 % between the measured initial mass of the droplet and the REA model's estimated value was reported.

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Unraveling the droplet drying characteristics of crystallization‐prone mannitol – experiments and modeling

Cited by 14 publications

References 53 publications

Bubble dynamics and atomization in evaporating polymeric droplets

Bubble dynamics and atomization in evaporating polymeric droplets

Unraveling Particle Formation: From Single Droplet Drying to Spray Drying and Electrospraying

Spray Drying of Cellulose Nanofibers: Drying Kinetics Modeling of a Single Droplet and Particle Formation

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