To keep the community actively engaged and connected between two IsoDays editions, we are happy to introduce the webinar series "Soft Discussions: Roads to the Isodays" covering various topics in soft matter. Each webinar, of  the duration of approximately 1 hour, will have the following format: 

Part1 - Ask me Anything!

Our Ask Me Anything (AMA) session is a unique opportunity to interact with an internationally renowned scientist in the field of soft matter. During the session, the expert  will answer a selection of questions from the audience, providing insights into his/her career, research work, and topics related to his/her experience as a soft matter scientist.

How it works:

1. Submit Your Questions: You have the chance to contribute to the conversation by submitting your questions in advance. 

2. Your Choice: When submitting your questions, you can choose whether to make your identity clear or remain anonymous.

3. Selection: Our team will review and select questions to ensure a diverse range of topics and interests are covered during the session. A moderator will facilitate the interaction by asking these selected questions to the expert.

Ready to Ask?

Get the chance to ask what you've never had the courage to ask your supervisor or colleague!  Use the form below to submit your questions and be part of this interactive session. We look forward to your participation!

Part 2 - Seminar

The AMA session will serve as an introduction to the second part of the webinar, during which another distinguished speaker will present on a cutting-edge topic related to soft matter science.

WEBINAR REGISTRATION

There is no fee to attend the webinar. To register, please follow the link below. The webinar series will be hosted on the Zoom platform. 

UPCOMING EVENTS:

Zoom Link for the webinar: https://uniroma1.zoom.us/j/83744800253

The event will run for approximately 1 hour and 15 minutes. The first half of the webinar will be dedicated to the 'Ask Me Anything' interview, while the second half will focus on the seminar, followed by a Q&A session.

Seminar information:

Title: Memristors and neuromorphic information processing with soft matter 

Speaker: René van Roij, Institute for Theoretical Physics, Utrecht University, The Netherlands 

Abstract: In this talk we will discuss recent advances in our understanding of the physics of coneshaped microfluidic channels under static and pulsatile voltage- and pressure drops. We will start with a basic introduction into electric double layers and electrokinetic phenomena such as electroosmosis and streaming on the basis of Poisson-Nernst-Planck-Stokes equations for transport of aqueous electrolytes. Building on this, we will show that the experimentally observed diode-like current rectification of cone-shaped channels follows from salt depletion (accumulation) at steady forward (backward) electric driving [1], which also explains the observed pressure-sensitivity of the electric conductance. An extension towards an applied AC voltage predicts these channels to be tunable between diodes at low frequencies ωτ<<1, memristors (resistors with memory) at intermediate frequencies ωτ ~ 1, and Ohmic resistors at high frequency ωτ>>1. Here the characteristic (memory retention) time τ is proportional to the square of the (easily controllable) channel length [2]. We then consider Hodgkin-Huxley-inspired iontronic circuits of short (fast) and long (slow) conical channels, and find neuromorphic responses akin to (trains of) action potentials [2] and several other neuronic spiking modes [3]. Interestingly, filling a tapered microfluidic channel with a nearly close-packed aqueous dispersion of colloidal charged spheres turns out to increase the memristive character of the channel [4], which upon applying trains of positive (negative) voltage pulses yields iontronic analogues of synaptic short-term potentiation (depression) that offers opportunities for reservoir computing -we give a proof of principle for the case of recognizing handwritten digits [4]. Finally we will also discuss recent and ongoing work on iontronic information processing. We exploit the mobility of the medium (water) by considering simultaneously applied pulsatile pressure and voltage signals to increase the bandwidth [5]. Finally, the versatile nature of the ionic charge carriers allows for Langmuir-like ionic exchange reaction kinetics on the channel surface [6], from which we predict direct iontronic analogues of synaptic long-term potentiation and coincidence detection of electric and chemical signals [7], which are both ingredients for brain-like (Hebbian) learning -all with aqueous electrolytes. 

References:

[1] W.Q. Boon, T. Veenstra, M. Dijkstra, and R. van Roij, Pressure-sensitive ion conduction in a conical channel: optimal pressure and geometry, Physics of Fluids 34, 101701 (2022). 

[2] T.M. Kamsma, W.Q. Boon, T. ter Rele, C. Spitoni, and R. van Roij, Iontronic Neuromorphic Signaling with Conical Microfluidic Memristors, Phys. Rev. Lett. 130, 268401 (2023).

 [3] T.M Kamsma, E. A. Rossing, C. Spitoni, and R. van Roij, Advanced iontronic spiking modes with multiscale diffusive dynamics in a fluidic circuit, Neuromorph. Comput. Eng. 4 024003 (2024). 

[4] T.M. Kamsma, J. Kim, K. Kim, W.Q. Boon, C. Spitoni, J. Park, and R. van Roij, Brain-inspired computing with fluidic iontronic nanochannels, PNAS 121, e23202242121 (2024).

 [5] A. Barnaveli, T.M. Kamsma, W.Q. Boon, and R. van Roij, Pressure-gated microfluidic memristor for pulsatile information processing, arXiv 2404.15006. 

[6] W.Q. Boon. M. Dijkstra, and R. van Roij, Coulombic Surface-Ion Interactions Induce Nonlinear and Chemistry-Specific Charging Kinetics, Phys. Rev. Lett. 130, 058001 (2023). 

[7] T.M. Kamsma, M. Klop, W.Q. Boon, C. Spitoni, and R. van Roij, manuscript in preparation

PAST WEBINARS

CONFIRMED GUESTS:

Prof. Daan Frenkel - University of Cambridge

Prof. Giovanni Ciccotti - University of Rome "Sapienza"

Prof. Cristina Marchetti - University of California, Santa Barbara

Prof. Kathleen J. Stebe - University of Pennsylvania

Prof. Margarida Telo de Gama - University of Lisbon

Prof. Robert Evans - University of Bristol

Prof. Francesco Sciortino - "Sapienza" University of Rome

Prof. Roberto Piazza - Politecnico di Milano

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