Related Experiment Video
Updated: Jul 16, 2026
08:20
Capillary-based Centrifugal Microfluidic Device for Size-controllable Formation of Monodisperse Microdroplets
Published on: February 22, 2016
Patterns formed by droplet evaporation from a restricted geometry.
1Departments of Materials Science and Engineering, Chemistry, and Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA. zqlin@iastate.edu
Journal of the American Chemical Society
|March 3, 2005
Summary
Evaporation of polymer drops in confined spaces creates hundreds of high-fidelity, regular concentric rings. This simple method enables versatile pattern generation for advanced applications.
Area of Science:
- Materials Science
- Fluid Dynamics
- Nanotechnology
Background:
- Evaporation-induced self-assembly is a common phenomenon.
- Controlling self-assembly for precise pattern formation remains challenging.
Purpose of the Study:
- To develop a simple, versatile, and generalizable method for creating highly regular patterns.
- To investigate the formation of concentric rings during drop evaporation in confined geometries.
Main Methods:
- Confined evaporation of a nonvolatile polymer solution.
- Microscopy and profilometry to analyze the resulting patterns.
Main Results:
- Hundreds of concentric rings, nanometers in height and micrometers in width, were consistently formed.
- The process demonstrated high fidelity and regularity in pattern generation.
- The method proved versatile and generalizable across different polymer solutions.
Conclusions:
- Evaporation from confined geometries offers a novel preparative strategy for pattern fabrication.
- This technique allows for the design of complex patterns with unprecedented precision.
- The findings open new avenues for micro- and nanofabrication.
Related Concept Videos
01:11Relative Velocity in Two Dimensions
Relative velocity is the velocity of an object as observed from a particular reference frame, or the velocity of one reference frame with respect to another reference frame. The concept of relative velocity can be used to describe motion in two dimensions. Consider a particle P and two reference frames S and S′. The position of the origin of S′ as measured in S is , the position of P as measured in S′ is , and the position of P as measured in S is , which can be evaluated by utilizing vector...
01:18pV-Diagrams
The pV diagram, which is a graph of pressure versus volume of the gas under study, is helpful in describing certain aspects of the substance. When the substance behaves like an ideal gas, the ideal gas equation describes the relationship between its pressure and volume. On a pV diagram, it is common to plot an isotherm, which is a curve showing p as a function of V with the number of molecules and the temperature fixed. Then, for an ideal gas, the product of the pressure of the gas and its...
01:18Streamlines, Streaklines, and Pathlines
A streamline represents the trajectory that is always tangent to the fluid's velocity vector at any given point. The velocity of a fluid particle is always directed along the streamline, ensuring the particle continuously follows the streamline's path. Streamlines are particularly useful for visualizing the overall direction of flow in a fluid system, and they provide an instantaneous representation of the flow's velocity field. In steady flow, where conditions do not change over time,...
01:25Design Example: Flow of Oil Through Circular Pipes
Understanding fluid flow behavior through pipes is critical in fluid mechanics, especially in applications like oil transportation through pipelines. Hagen-Poiseuille's law provides an exact solution derived from the Navier-Stokes equations for steady, incompressible, and laminar flow within a circular pipe. Hagen-Poiseuille's law helps determine the necessary pressure drop across a pipeline section by determining parameters like pipe length, radius, oil viscosity, and the desired volumetric...
01:19Polar Curves
The spirograph is a versatile tool for visualizing the relationship between geometry and mathematical representation. In particular, it demonstrates how polar coordinates offer an alternative framework for describing curves in comparison to Cartesian coordinates. Instead of specifying a point by its horizontal and vertical displacements (x, y), polar coordinates use a radius r, the distance from the origin, and an angle θ, measured counterclockwise from the polar axis. This system is...
01:26Vector Forms of Green’s Theorem
The study of fluid motion often involves understanding how local rotational behavior relates to global circulation. In the context of a pond with pollutants, direct measurement of water movement along an irregular shoreline can be impractical. Green’s Theorem in vector form provides an alternative by relating the circulation around a closed boundary to properties of the flow within the enclosed region.Measurements of water velocity at different points define a continuous vector field that...