Electrowetting actuation of gold nanofluid droplets: a physics dissertation defense by Crismar Patacsil

ateneophysicsnews_crismar_patacsil_dissertation_defense_20170408 (2)
The Department of Physics of Ateneo de Manila University cordially invites you to a Physics Dissertation Defense:

  • PhD candidate: Crismar P. Patacsil
  • Date and Venue: April 8, 2017, 1:00 PM at Faura Hall F-106

Panel members:

  • Raphael A. Guerrero, Ph.D., Dissertation Supervisor
  • Benjamin O. Chan, Ph.D., Dissertation Examiner
  • Gil Nonato C. Santos, Ph.D., Dissertation Examiner
  • Erwin P. Enriquez, Ph.D., Dissertation Reader
  • Joel T. Maquiling, Ph.D., Dissertation Reader

Nanoparticles exhibit completely different properties (physical, chemical, electronic, magnetic and optical) from their bulk material counterparts. This study explores the interaction of gold nanoparticle (AuNP) suspensions in a liquid droplet with an applied electric field. A basic planar electrowetting set-up is employed, consisting of a bottom copper electrode coated with a thin insulating layer of uncured polydimethysiloxane (PDMS) silicone oil mounted on an adjustable stage and a platinum wire upper electrode in contact with the sessile gold nanofluid droplet sitting on the dielectric layer. A voltage source is connected across the top and bottom electrodes. Changes in the contact angle of the droplet, as voltage is varied, is captured using a USB microscope camera. The contact angles of the images are determined using ImageJ software. The electrowetting on dielectric (EWOD) experiment is done with varying concentrations (in µM) of gold nanofluid (deionized water containing gold nanoparticles with an average size of 10 nm): 0.5, 0.33, 0.25, 0.05 and deionized water (no gold nanoparticles) as a control fluid. Results show a different electrowetting response for each concentration. The contact angle is found to decrease with increasing nanoparticle concentration, indicating a decrease in the liquid-gas surface tension as concentration increases. Increasing the nanoparticle content also lowers the required voltage for effective actuation. Contact angle saturation is observed with nanofluid droplets, with the threshold voltage decreasing as nanoparticle concentration rises. Maximum droplet actuation before contact angle saturation is achieved at only 10 V for a concentration of 0.5 μM. To explain the mechanism for the observed enhanced electrowetting actuation, the specific capacitance C is calculated from the voltage versus contact angle data for each concentration. For the control fluid, the calculated specific capacitance is 0.0012 F/m^2. Specific capacitances are C = 0.0097 F/m^2, C = 0.0049 F/m^2, and C = 0.0015 F/m^2 for 0.5µM, 0.33µM, and 0.05µM gold nanofluid concentrations, respectively. The presence of gold nanoparticles affects electrowetting response by increasing the capacitance with increasing concentration of the nanoparticles. Higher specific capacitance results in increased induced charges at the solid-liquid interface which would result in increased electro-mechanical force on the droplet as voltage is applied.

Ateneo Physics Talk: “Smart colloids and wet nanotechnology: From reinforced Kevlar to targeted therapeutic proteins” by Dr. Dan Zarraga of Genentech

Dr. Dan E. Zarraga

Dr. Dan E. Zarraga

Title: Smart colloids and wet nanotechnology: From reinforced Kevlar to targeted therapeutic proteins

Dr. Dan E. Zarraga
Late Stage Pharmaceutical Development Department

Date and time: February 10, 2014 (Monday) at 4:30 pm – 5:30 pm

Venue: Faura 113


Progress in colloid science and genetic engineering in the last decade has allowed for the design of smart soft materials and protein drugs at unprecedented levels of detail at the nanoscale. This advent of wet nanotechnologies has opened up application opportunities in soft materials, industrial biology, vaccines, and therapeutic proteins. A brief background on colloid science and protein engineering will be given, then a selection of recent advances and their applications ranging from protective clothing, industrial enzymes, vaccines and targeted protein therapeutics (for cancer, neuroscience, etc) will be described. A short description of unique biophysical techniques to characterize these wet nanotechnologies will also be given, such as small angle neutron scattering, dynamic light scattering, and cryo-electron microscopy. Finally, a glimpse into the potential future applications of wet nanotechnology will be provided.

About the speaker:

Dr. Zarraga obtained his B.S. in Chemical Engineering from the University of the Philippines in 1993 and completed his Ph.D. in Chemical Engineering at the University of Notre Dame in the U.S. in 2000. During his graduate work, he conducted fundamental research on solid-liquid suspensions relevant to a wide variety of industries from solid-liquid rocket fuels to lightweight polymer composites for aircraft and sports applications. He was an industry-academe Postdoctoral Fellow at the Georgia Institute of Technology in Atlanta in collaboration with Abbott Pharmaceuticals in Chicago in 2001, where he worked on the microenapsulation of drugs in biopolymers using spray congealing technology. He was then hired as a Senior Engineer in 2002 at 3M Pharmaceuticals in St. Paul Minnesota where he developed a technology platform for the novel drug delivery of immune response modifiers (IRMs) for prophylactic and therapeutic vaccines. In 2007, Dr. Zarraga moved to San Francisco to join Genentech’s Late Stage Pharmaceutical Development department as a Manager leading the formulation, development, and process characterization efforts for protein therapeutics. He occasionally teaches part-time at Santa Clara University, a Jesuit institution, as an Adjunct Faculty of Bioengineering. He sits on the industrial board of two private-public consortia, BITC (Biomolecular Interaction Technology Center) and nSOFT (Neutron Scattering of Soft Materials), based at the University of Delaware and the National Center for Neutron Research (NCNR) in Maryland, respectively. He is a frequently invited speaker at conferences, including the American Conference on Neutron Scattering, the Society of Rheology, and the American Institute of Chemical Engineers. Dr. Zarraga also actively participates in the Philippine International Aid (PIA) group in San Francisco in support of under-educated youth in Philippine provinces.

Lawrence Gochioco in Business Mirror: From an average Ateneo physics student to among the top practicing geophysicists in the US and the world

Lawrence Gochioco of Geo-Nano Technology Corporation

Lawrence Gochioco of Geo-Nano Technology Corporation

From the Business Mirror:

Gochioco obtained his Physics degree from the Ateneo de Manila University (AdMU) in 1978.

Considered an average student in the rigorous Ignatian academic program, he managed to balance his academics and extra-curricular activities by playing varsity volleyball and track and field since his high-school freshman year. He led both teams to back-to-back NCAA (National College Athletic Association) championships. In recognition of his athletic achievements, he was inducted into the Ateneo Sports Hall of Fame in 2009.

The 1970s oil crises had a major impact on his decision to pursue a career in geophysics. Intrigued by the popular 1970s TV show Dallas—on the power of oil and energy in geopolitics—Gochioco decided to go to the US to study and learn the latest innovative technologies for petroleum and mineral exploration. After graduation, he taught college physics for two years at AdMU. He later received a full scholarship from Ohio University in 1980 to pursue his graduate studies in Physics. Aside from the regular course load, he took additional subjects in geology and geophysics.

In 1982 the US oil industry began to contract, resulting in thousands of jobs lost. He moved to Houston despite the poor jobs market. The first four years of his career were turbulent. As a survivor, he is always prepared for the worst-case scenario and developed back-up systems. After each layoff, he found better career opportunities with greater responsibilities. These varied technical and management positions later provided him the diverse skills needed to establish his own businesses and joint ventures.

In 1989 Gochioco published his first technical paper in Geophysics, and many more papers and feature articles soon followed. In recognition of his contributions, he was nominated to the prestigious TLE Editorial Board of the Society of Exploration Geophysicists (SEG) in 2000 and later became chairman during his 2003-2004 term. He was the first Asian ever to become the editorial board chairman.

(Read more at the Business Mirror)

Some additional notes:

Gochioco became an entrepreneur in 2004 when he formed his first geophysical consulting and field services company.  In 2007, his business expanded internationally starting with projects in Mongolia.  Thereafter, he formed joint ventures and acquired equity stakes in various companies in the US, Mongolia, and the Philippines.  From the ridge tops of the US Appalachia Mountains down to the Mongolian Gobi Desert and into the bowels of underground coal mines, Gochioco is a “hands-on” geophysicist who is ready to tackle the world’s most grueling exploration challenges.  He said that his vigorous competitive training and discipline from his past NCAA varsity sports helped him focus.  Moreover, he applies his robust analytical skills to manage his diversified portfolio in the global stock and commodities markets.  His investments now encompass oil, gas, coal, renewable energies, minerals (gold, silver, copper, iron ore, and rare earths), real estate, banking, emerging technologies, and nanotechnologies.

Ateneo Physics alumni Dr. Lawrence Millard C. Gochioco (BS Ps ’78) of GeoNano Technology Corporation to give a talk on “Global energy challenges and geophysics”

Dr. Lawrence Millard C. Gogioco


by Dr. Lawrence Millard C. Gochioco

GeoNano Technology Corporation

Date: 29 Jan 2011 (Sat)
Time: 10:00-11:00 a.m.
Venue: Faura 318


The recent global economic crisis temporarily lessened global demands for energy which could create a misguided mind set that there are no near-term impeding energy crises. When the global economies slowly recover however, energy resource demands will strain the system again as spare capacities are extremely limited. Statistical data will be presented from key reliable sources on the production and consumption of hydrocarbons and renewables sources, coupled with projected future needs to meet the ever increasing energy demands of growing economies in particular Asia.

The role of a physicist/geophysicist is highlighted to address a good portion of the complex energy markets. Career choices and opportunities are also presented to demonstrate the importance of developing and applying innovative and nano technologies across the wide spectrum of the upstream and downstream sectors of the energy fields Students will eventually gain valuable insights into the challenges and opportunities associated with various energy issues.

Ateneo Physics News: Dr. Lawrence Millard C. Gochioco is an alumni of the Ateneo Physics Department (BS Ps ’78).

Zoraida P. Aguilar, PhD of Ocean NanoTech LLC to give a talk this 16 Dec 2010 at Schmitt Hall: “Engineered anomaterials for Biomedical Applications”


Engineered Nanomaterials for Biomedical Applications

Room 109, Schmitt Hall, Chemistry Department, Ateneo de Manila University, 15 Dec 2010, 4:30 p.m.

Director of R&D, Ocean NanoTech LLC, Springdale, AR


Engineered nanomaterials (ENMs) such as quantum dots, metal nanoparticles such as gold and silver, metal oxides like tin oxide nanoparticles, magnetic nanoparticles, liposomes, etc are a new class of materials. These have unique properties that include 3-100 nm diameter, signal brightness, low photo bleaching, high magnetic and electric properties, broad excitation spectrum, narrow bandwidth, and simultaneous excitation of multiple fluorescent colors. Quantum dots are unique in their emission spectra even with the use of ordinary source of light while magnetic nanoparticles are unique because of their highly magnetic nature.

The unique advantages of quantum dots as fluorescent labels increase the brightness under photon-limited conditions where light intensities are severely attenuated by scattering and absorption. This permits detection down to single nanoparticle level that lead to reliable quantification of binding and transport phenomena. The cross section of some QDs that may be 60 times larger than that of organic dye results in brightness that can be one or two orders of magnitude higher improving detection limit. As a result, quantum dots are used in a broad range of applications including single molecule biophysics, biomolecular profiling, optical barcoding, in vivo and in vitro imaging, targeted drug delivery, and other medical applications.

The biomedical imaging application of quantum dots lead to the fluorescence detection of breast cancer cell, prostate cancer cells, etc. Magnetic iron oxide nanoparticles have been studied for drug delivery, capture and isolation of target cells, MRI contrast agents, etc. Various examples of these biomedical applications of engineered nanomaterials will be discussed.80