We report single-step fabrication and characterization of PDMS microlens and demonstrate its use in optocapillary flow manipulation. Mixed PDMS droplets are dispensed over a thermally controlled Si substrate and cured to obtain microlenses. The spreading characteristics of sessile PDMS droplets are measured with time and substrate temperature. The gel-time of PDMS drops is studied for various substrate temperatures. The micro lenses are characterized based on the numerical aperture, focal length, f/number, optical transparency and spot size. Finally, micro lenses are used for focusing light from a low power IR laser for the manipulation of capillary flow in a microchannel. © 2015 Elsevier B.V. All rights reserved.

Ashis Kumar Sen

Department of Mechanical Engineering

Sreekant Damodara

Derosh George

Drops

Lenses

Microchannels

Fabrication and characterizations

FLOW MANIPULATION

NUMERICAL APERTURE

Optical transparency

PDMS MICROLENS

SPREADING CHARACTERISTICS

Substrate temperature

Various substrates

MICROLENSES

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Sensors and Actuators, B: Chemical

This work reports experimental and theoretical studies of hydrodynamic behaviour of deformable objects such as droplets and cells in a microchannel. Effects of mechanical properties including size and viscosity of these objects on their deformability, mobility, and induced hydrodynamic resistance are investigated. The experimental results revealed that the deformability of droplets, which is quantified in terms of deformability index (D.I.), depends on the droplet-to-channel size ratio q and droplet-to-medium viscosity ratio k. Using a large set of experimental data, for the first time, we provide a mathematical formula that correlates induced hydrodynamic resistance of a single droplet DRd with the droplet size q and viscosity k. A simple theoretical model is developed to obtain closed form expressions for droplet mobility / and DRd. The predictions of the theoretical model successfully confront the experimental results in terms of the droplet mobility / and induced hydrodynamic resistance DRd. Numerical simulations are carried out using volume-of-fluid model to predict droplet generation and deformation of droplets of different size ratio q and viscosity ratio k, which compare well with that obtained from the experiments. In a novel effort, we performed experiments to measure the bulk induced hydrodynamic resistance DR of different biological cells (yeast, L6, and HEK 293). The results reveal that the bulk induced hydrodynamic resistance DR is related to the cell concentration and apparent viscosity of the cells. © 2014 AIP Publishing LLC.

Fulltext

Biomicrofluidics

Hydrodynamic resistance and mobility of deformable objects in microfluidic channels

Arabian Journal of Chemistry

Density, viscosity, surface tension, and molar volume of propylene glycol + water mixtures from 293 to 323 K and correlations by the Jouyban–Acree model

International Journal of Information and Education Technology

Automatic Test Data Generation-Achieving Optimality Using Ant-Behaviour

Journal of Micromechanics and Microengineering

Fabrication of adjustable-morphology lens based on electrohydrodynamic for high-power light-emitting diodes

Optics Express

Rapid fabrication of thermoplastic polymer refractive microlens array using contactless hot embossing technology

Single step fabrication and characterization of PDMS micro lens and its use in optocapillary flow manipulation

Journal	Data powered by TypesetSensors and Actuators, B: Chemical
Publisher	Data powered by TypesetElsevier
ISSN	09254005
Open Access	No