Colloidal devices

HOME Velegol Family Wild Scholars Penn State Students Colloidal Devices

We make doublets and other assemblies. If you have a need to fabricate or pattern particles, drop me an email.

Our niche … scalable, general

This is an exciting time for those of us who study how to fabricate colloidal assemblies. There are so many outstanding techniques! Janus particles, dielectrophoretic assembly, surface tension assembly.

Our niche is simple. We aim to build colloidal assemblies out of a general set of particles – metals, oxides, polymers, semiconductors, hydrogels – and to do so in a scalable manner. The outstanding students who work on this with me are listed below. Go ahead and contact them!

We have two techniques for assembly:

- “salting / quenching / fusing” (SQF) for doublets

- particle lithography

The SQF technique can produce doublets out of any material we have tried – as shown on the right – in the time it takes you to read this web page. Quick. The particle lithography technique can produce more sophisticated assemblies, with just a bit more effort.

If you have an application where you need to fabricate particles together, contact us. We’d love to help.

Students (as of Summer 2006)
Huda Jerri (PhD expected Dec 2009) – “Colloidal syringes”
Joe McDermott (PhD expected Dec 2010) – “Colloidal Photoelectrochemical Cells”
Neetu Chaturvedi (PhD expected Dec 2010) – “Colloidal Photoelectrochemical Cells”

Laura Ramirez (PhD expected Dec 2011) – “Polloidal Chains”

Cesar Serrano (MS expected Aug 2010) – “Sedimentation Separations”

Tso-Yi Chiang (PhD expected Dec 2012) – “Gravimetric Membrane Separations”

Links
ACS Colloids & Surface Science Division
NanoHub computation website
NIH submission dates
Penn State MRSEC: Center for Nanoscale Science
Penn State Handbooks online

Making doublets the easy way

How hard is it to fabricate colloidal machines and devices? Hard.  But making doublets – a component of the devices – is easy.  See how in Langmuir 22, 9135 (2006).  Email Velegol for more info.  See other news.

Nanoscale van der Waals forces

Does Lifshitz theory describe VDW forces for nanocolloids?  Not very well. See part of the story in J Chem Phys 124, 074504 (2006).

End-on bacterial adhesion

Do bacterial stick end-on to surfaces? E coli K12 D21 sure do.  See our article in Colloids & Surfaces B, 50, 66-71 (2006).  Email Velegol for more info.  See other news.

Nanoscale Clausius-Mossotti equation

Does the permittivity describe a material’s properties at the nanoscale?  Nope.  Atoms within 10 atoms of the surface behave differently since surface atoms have a different coordination, and bulk permittivities are not found until a particle has about 1000 atoms.  See our article in Phys. Rev. A, 72, 053201 (2005).  Email Velegol for more info.  See other news.

Electrokinetic nanomotors (with Professors Sen and Mallouk in Penn State Chemistry)

Can particles be moved autonomously by adding H₂O₂ “fuel” to a system?  Take a look at our collaboration on “catalytic micropumps” (Kline et al, J. Am. Chem. Soc., 127, 17150, 2005).  Email Velegol for more info.  See other news.

Measuring charge nonuniformity

Think measuring charge nonuniformity takes too long?  The Velegol lab group has developed a light scattering method for doing it in seconds (Colloids Surf A, 267, 79, 2005).

Joe Jones, PhD (Oct 2005)
Joseph F. Jones passed his PhD defense in October 2005, and will graduate on 17 Dec 2005.  His thesis was on “Examining initial bacterial adhesion: oriented adhesion and surface nanodomains”.  Joe starts at the Center for Naval Analysis in January 2006.  Congratulations Joe!

Charles Snyder passes candidacy exam (Aug 2005)
Charles Snyder passed his PhD proposal on “Site Specific Functionalization of Colloids through Particle-Lithography: Developing, Understanding, and Scaling”.  Congratulations and welcome to the PhD program Charles!

Sabrina Marie Velegol (July 2005)


Sabrina Marie Velegol was born Sun 17 July 2005, and so now Lauren is a “big sister”.  The whole family is doing well. 

Velegol funded by Petroleum Research Fund Grant (July 2005)
Darrell Velegol and his lab group received $80 000 in funding through grant PRF# 43453-AC10, for a proposal entitled Site-specific chemistry on colloidal particles by “particle lithography”.

“colloidal molecules” (July 2005)


Can particles form “colloidal molecules” just as atoms form organic compounds? Snyder, Yake, Feick, and Velegol show how “particle lithography” does this (Langmuir 21, 4813, 2005).


core-shell particles to reduce van der Waals forces (June 2005)

Can co-solvents be used to stabilize nanocolloids, even without the use of bulky dispersant molecules?  Cole and Velegol think it’s possible (Nano Lett 5, 169, 2005).