Center for Soft Matter and Biological Physics Seminars

Fall 2018

Organizer: Vinh Nguyen

These meetings occur on Mondays from 4:00pm to 5:00pm in Robeson 304.
Refreshments are served before the semnars (unless otherwise indicated)

August 2018
August 20

Monday 4:00pm
304 Robeson Hall
Joint CM Seminar
(poster)

Prof. Surita Bhatia (Stony Brook University, NY)

"Stratification in Colloidal Films"

Multicomponent films based on colloidal dispersions have a wide range of applications, including antimicrobial coatings for medical instruments, conductive textiles for flexible electronics, anti-reflective coatings for optical devices, paints for humid environments that are resistant to mold growth, and drug-loaded coatings for medical implants. Often, there is a need to spatially control location of certain components in the film. For example, silver nanoparticles can be used to impart antimicrobial activity to paints, but this component is expensive and may only be needed in the top few layers of the coating, not throughout the entire film. In principle, evaporative drying of multicomponent dispersions can be used to create films with a prescribed vertical concentration profile in a one-step process. In this talk, we present our recent results from atomic force microscopy (AFM) and small-angle X-ray scattering (SAXS) on films prepared from binary colloidal dispersions containing large and small particles of varying size and initial volume fraction. Our results show evidence of different types of stratification behavior, including large-on-top (e.g., large particles migrating to the top surface of the film), small-on-top, and “sandwich”-like layering. We discuss these results in terms of recent theories for stratification during evaporative drying..

Host: Shengfeng Cheng

August 27

Monday 4:00pm
304 Robeson Hall
Joint CM Seminar
(poster)

Dr. Kunal Mondal (North Carolina State University)

"Soft-Nano-materials, Interfaces, and Micro-Nano-fabrication to Build Tools and Functional Devices"

New competitive technologies should be developed to deal with the world’s emerging problems in healthcare, environmental, agriculture, energy and security sectors to benefit a broad spectrum of society while using minimal resources. Multifunctional interfaces of nanomaterials can be used to tackle such glitches by developing sensors and detection devices such as biosensors, explosives trace detectors, mechanical-stress sensors, wastewater management systems and energy storage devices owing to their nanoscopic surface properties. Considering this, several catalytic and photocatalytic metal/metal-oxide semiconductor nanostructures have been synthesized and used for environmental remediation, point-of-care diagnostics and energy storage applications. Several fabrication techniques including electrospinning, microfabrication, 3D printing etc. have been used to made functional nano/micro devices. Various physicochemical characterization techniques are used to study their properties in nanoscale. Furthermore, effort has been made on surface patterning and fabricating stretchable electronics by integration of conducting liquid metal in soft elastomers to explore ways to utilize these ‘softer than skin’ materials for bioelectronic applications. Finally, this concludes with an outlook and future challenges of these materials within this context.

Host: Rana Ashkar

September 2018
September 3

Monday 4:00pm
304 Robeson Hall
(poster)

Labor Day "No CSB Seminar Scheduled"

Host:

September 10

Monday 4:00pm
304 Robeson Hall
(poster)

Host:

September 17

Monday 4:00pm
304 Robeson Hall

(poster)

Chengyuan Wen (Virginia Tech, Physics)

Host: Vinh Nguyen

September 21

Friday, 2:30pm
210 Robeson Hall
Special Seminar
(poster)

Prof. Gary Grest (Sandia National Laboratories, Albuquerque, NM)

"Going up in time and length scales in modeling polymers"

Polymer properties depend on a wide range of coupled length and time scales, with unique macroscopic viscoelastic behavior stemming from interactions at the atomistic level. The need to probe polymers across time and length scales and particularly computational modeling is inherently challenging. Here new paths to probing long time and length scales including introducing interactions into the traditional bead-spring model that has been widely used for the past thirty years and coarse graining of atomistic simulations will be compared. Using linear polyethylene as a model system, the degree of coarse graining with two to six methylene groups per coarse-grained bead derived from a fully atomistic melt simulation were probed. Using these models we were successful in probing highly entangled melts and were able reach the long-time diffusive regime which is computationally inaccessible using atomistic simulations. We simulated the relaxation modulus and shear viscosity of well-entangled polyethylene melts for scaled times of a microsecond. The long time and length scale is coupled to the macroscopic viscoelasticity where the degree of coarse graining sets the minimum length scale instrumental in defining polymer properties and dynamics. Results will be compared to those obtained from the bead-spring model to demonstrate the additional insight that can be gained from atomistically inspired coarse grained models.

Host:Shengfeng Cheng

September 24

Monday 4:00pm
304 Robeson Hall

(poster)

Host:

September 28

Friday, 2:30pm
210 Robeson Hall
Special Seminar
(poster)

Prof. Daniel I Goldman (Georgia Tech )

"Robophysics: Physics Meets Robotics"

Robots will soon move from the factory floor and into our lives (e.g. autonomous cars, package delivery drones, and search-and-rescue devices). However, compared to living systems, locomotion by such devices is still relatively limited, in part because principles of interaction with complex environments are largely unknown. In this talk I will discuss efforts to develop a physics of moving systems -- a locomotion ``Robophysics'' -- which we define as the pursuit of the discovery of principles of self-generated motion [Aguilar et al, Rep. Prog. Physics, 2016]. We use the methods of physics to examine successful and failed locomotion in simplified laboratory devices using parameter space exploration, systematic control, and techniques from dynamical systems. Drawing from examples from my group and our collaborators, I will discuss how robophysical studies in terrestrial environments have inspired new physics questions in low dimensional dynamical systems (including creation of analog quantum mechanics and gravity systems) and soft matter physics, have been useful to develop models for biological locomotion in complex terrain, and have begun to aid engineers in the creation of devices that begin to achieve life-like locomotor abilities on and within complex environments. The rapidly decreasing cost of constructing sophisticated robot models with easy access to significant computational power bodes well for scientists and engineers to engage in a discipline which can readily integrate experiment, theory and computation.

Host: Uwe Tauber

October 2018
October 1

Monday 4:00pm
304 Robeson Hall
CM Seminar
(poster)

Dr. Jennifer Cano (Princeton University)

"TBD"

Host: Kyungwha Park

October 8

Monday 4:00pm
304 Robeson Hall

(poster)

Prof. David M. Leitner (University of Nevada, Reno )

“Watching energy transport in proteins: Identifying dynamics networks and thermodynamic properties”

Energy transport in a protein mediates protein function and represents the early events following a reaction or photoexcitation.  New time-resolved measurements, and a variety of computational and theoretical methods allow us to map out and describe energy transport in great detail.  I will describe some of our theoretical and computational work on the nature of energy transport in proteins, with focus on what we can learn about protein dynamics and thermodynamics by watching energy flow in proteins.  By coarse graining energy transport dynamics from the all-atom to residue level, we have identified a relation between conformational dynamics at equilibrium and rates of energy transfer across non-bonded contacts.  Measurements of rates of energy transfer thus provide a window into equilibrium dynamics of proteins and entropy associated with the dynamics of the contact.

Host:Vinh Nguyen

October 15

Monday 4:00pm
304 Robeson Hall

(poster)

Jacob Carroll (Virginia Tech, Physics)

"TBD"

Host: Uwe Tauber

October 22

Monday 4:00pm
304 Robeson Hall

(poster)

Host:

October 29

Monday 4:00pm
304 Robeson Hall

(poster)

Host:

November 2018
November 5

Monday 4:00pm
304 Robeson Hall
Joint CM Seminar
(poster)

Brian Skinner (Massachusetts Institute of Technology)

Host: Uwe Tauber

November 12

Monday 4:00pm
304 Robeson Hall

(poster)

Shadi Esmaeili (Physics, Virginia Tech)

"TBD"

Host: Vinh Nguyen

November 19

Monday 4:00pm
304 Robeson Hall

(poster)

Host:

November 26

Monday 4:00pm
304 Robeson Hall

(poster)

Shannon Serrao (Physics, Virginia Tech)

"TBD"


Host: Vinh Nguyen

December 2018
December 3

Monday 4:00pm
304 Robeson Hall
(poster)

Prof. Sarah Perry (University of Massachusetts, Amherst)

"TBD"

Host: Vinh Nguyen

December 10

Monday 4:00pm
304 Robeson Hall
(poster)

Host:

December 17

Monday 4:00pm
304 Robeson Hall
(poster)

Host:

Center for Soft Matter and Biological Physics Seminars

Spring 2019

Organizer: Vinh Nguyen

These meetings occur on Mondays from 4:00pm to 5:00pm in Robeson 304.
Refreshments are served before the semnars (unless otherwise indicated)

January 2019
January 21

Monday 4:00pm
304 Robeson Hall
(poster)

"Martin Luther King Holiday (No Classes-University Offices Closed)

Host:

January 28

Monday 4:00pm
304 Robeson Hall
(poster)

Host:

February 2019
February 4

Monday 4:00pm
304 Robeson Hall
(poster)

Host:

February 11

Monday 4:00pm
304 Robeson Hall
(poster)

Host:

February 18

Monday 4:00pm
304 Robeson Hall

(poster)

Host:

February 25

Monday 4:00pm
304 Robeson Hall

(poster)

Host:

March 2019
March 1

Friday, 2:30pm
Special Seminar
210 Robeson Hall
(poster)

Prof. Maikel Rheinstadter (McMaster University)

Host: Rana Ashkar

March 4

Monday 4:00pm
304 Robeson Hall

(poster)

Host:

March 11

Monday, 4:00pm
304 Robeson Hall

(poster)

Host:

March 18

Monday 4:00pm
304 Robeson Hall

(poster)

Host:

March 22

Friday 2:30pm
210 Robeson Hall
Special Seminar
(poster)

Prof. Matt Helgeson (UC Santa Barbara)

"TBD"

Host: Rana Ashkar

March 25

Monday 4:00pm
304 Robeson Hall

(poster)

Host:

April 2019
April 1

Monday 4:00pm
304 Robeson Hall

(poster)

Host:

April 8

Monday 4:00pm
210 Robeson Hall

(poster)

Host:

April 15

Monday 4:00pm
304 Robeson Hall

(poster)

Host:

April 22

Monday 4:00pm
304 Robeson Hall

(poster)

Host:

April 29

Monday 4:00pm
304 Robeson Hall

(poster)


Host:

May 2019
May 6

Monday 4:00pm
304 Robeson Hall
(poster)

May 13

Monday 4:00pm
304 Robeson Hall
(poster)

Final Exam Week. No Seminar Scheduled.