Friction behavior of rough polydimethylsiloxane surfaces under hydrophobic polymer aqueous solution conditions

High encapsulation efficiency of magnetite nanoparticles (MNPs; Fe3O4) in microcapsules using PDVB as a hydrophobic polymer shell was successfully achieved by microsuspension conventional radical polymerization (ms CRP). MNPs were initially synthesized by co-precipitation of Fe2+/Fe3+ in a binary phase. During the nucleation of MNPs in alkaline aqueous solution existing oleic acid (OA), MNPs were coated with OA (MNPs-OA) before moving to the toluene phase with the addition of salt. At OA concentration of 0.3 wt%, most of the nucleated MNPs were hydrophobic and well dispersed in the toluene phase. Using DVB as a monomer for ms CRP, high encapsulation efficiency (92 %EE) of MNPs-OA was obtained, with low free polymer particle formation. By contrast, large amounts of free polymer particles were observed at low %EE (32%) of MNPs. The main driving force for high %EE was obtained by coating the surface of the MNPs by OA which increased hydrophobicity.

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Study on the Characteristics of Flow and Heat Transfer of Polymeric-Fluid-Based Cu Nanofluids

Volume 1B, Symposia: Fluid Measurement and Instrumentation; Fluid Dynamics of Wind Energy; Renewable and Sustainable Energy Conversion; Energy and Process Engineering; Microfluidics and Nanofluidics; Development and Applications in Computational Fluid Dynamics; DNS/LES and Hybrid RANS/LES Methods ◽

10.1115/fedsm2017-69006 ◽

2017 ◽

Author(s):

Weihua Cai ◽

Yongyao Li ◽

Yue Wang ◽

Xin Zheng ◽

Mengsheng Zhu

Keyword(s):

Heat Transfer ◽

Aqueous Solution ◽

Shear Stress ◽

Wall Shear Stress ◽

Drag Reduction ◽

Volume Fraction ◽

Solution Flow ◽

Flow And Heat Transfer ◽

Wall Shear ◽

Polymer Aqueous Solution

In this paper, we propose a new fluid: drag-reducing-fluid-based nanofluids (DRFBN), i.e., nanoparticles are added into polymer aqueous solution. In order to investigate the flow and heat transfer characteristics of this new fluid, the Reynolds stress turbulence model and equivalent viscosity model are used in the simulations. Wall shear stress and Nusselt number (Nu) are chosen to represent the effects of drag reduction and heat enhancement respectively. The numerical studies mainly focus on the effects of different parameters on wall shear stress and Nu. The results show that comparison with water flow, DRFBN flow still has remarkable drag-reducing effect; comparison with polymer aqueous solution flow, DRFBN flow has some improvement on heat transfer. Therefore, DRFBN has duel effects: drag reduction and heat transfer enhancement. Besides, it is found that the parameters of nanoparticle volume fraction, Reynolds number and drag-reducing parameter have remarkable effects on wall shear stress and Nu of DRFBN flow.

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The relationship between the adhesion work, the wettability and composition of the surface layer in the systems polymer/aqueous solution of anionic surfactants and alcohol mixtures

Applied Surface Science ◽

10.1016/j.apsusc.2010.08.012 ◽

2010 ◽

Vol 257 (3) ◽

pp. 1034-1042 ◽

Cited By ~ 19

Author(s):

Anna Zdziennicka ◽

Bronisław Jańczuk

Keyword(s):

Aqueous Solution ◽

Surface Layer ◽

Anionic Surfactants ◽

Alcohol Mixtures ◽

Polymer Aqueous Solution ◽

The Relationship ◽

Adhesion Work

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Effect of Hydrophobic Polymer Application and Irrigation Rates on Yield of Field Grown Okra

Journal of Agricultural and Marine Sciences [JAMS] ◽

10.24200/jams.vol6iss0pp67-75 ◽

2001 ◽

Vol 6 ◽

pp. 67

Author(s):

P. Cookson ◽

H. AbdelRahman ◽

P. Hirsbrunner

Keyword(s):

Aqueous Solution ◽

Water Resources ◽

Water Use ◽

Irrigation Water ◽

Untreated Control ◽

Total Yield ◽

Latin Square ◽

Hydrophobic Polymer ◽

Water Use Efficiencies ◽

Polymer Application

Improving irrigation efficiency is of great importance in conserving water resources of arid countries. The effect of a hydrophobic polymer (called Guilspare) to improve yields and water use efficiencies of okra (Adelmoschus esculentus) plants was investigated using a 3x3 Latin Square field experiment. Soils were treated with Guilspare by spraying the surface with an aqueous solution and left to dry. Yields of okra, planted in April and October, were assessed from plots receiving two rates of Guilspare application against an untreated control. Each column within the design received irrigation water at separate rates. Yields and water use efficiencies were generally higher, and a higher proportion of the total yield was harvested earlier, from Guilspare treated than untreated plots. Comparisons of yields from treated plots receiving lowest irrigation rates and untreated plots receiving the highest irrigation rate, suggested that similar yields can be obtained by using the polymer with, approximately, 25% and 50% less water in summer and in winter, respectively.

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