Stefania Ketzetzi


Last Name

Ketzetzi

First Name

Stefania

ORCID

0000-0003-1482-5110

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2024 - 20253
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Publications 1 - 3 of 3
  • Active Colloidal Molecules with Dynamic Configurational Freedom
    Item type: Journal Article
    Ketzetzi, Stefania; Caprini, Lorenzo; Willems, Vivien; et al. (2025)
    ACS Nano
    Molecular machines and microorganisms employ dynamic shape changes to enable adaptive function. In contrast, active colloidal machines and micromotors, their synthetic counterparts, are typically preconfigured and mechanically rigid, which limits the range of their dynamic behavior and thereby their functionality. Here, through physical interactions alone, we assemble active colloidal molecules with flexible configurations that evolve freely and continuously in time. Unlike existing colloidal systems that either offer structural flexibility in passively diffusing assemblies, or impose fixed configurations in self-propelling ones, our colloidal molecules both dynamically self-assemble and disassemble on demand and directly propel themselves through their own internal restructuring. This, in turn, bestows enhanced self-regulation, self-steering, and avoiding capabilities upon encountering other molecules. These capabilities suppress clustering and motility-induced phase separation, allowing them to remain dispersed, well-separated, and still actively moving even at high concentrations. Micromotors with dynamic configurational freedom thus constitute a step toward autonomous motion beyond classical synthetic active matter, and allow for designing “intelligent” microrobots and responsive functional active materials at the nano- and microscale.
  • Active Colloids in Complex Environments
    Item type: Book Chapter
    Ketzetzi, Stefania; Simmchen, Juliane; Isa, Lucio (2024)
    RSC Soft Matter ~ Active Colloids: From Fundamentals to Frontiers
    This chapter provides an overview of the effects of complex environments on active colloids. We start with solid boundaries and confining structures, highlight interactions with colloids and other “softer” passive objects, and show parallels with behaviours observed when particles move close to – or directly at – interfaces. In the second half, we address complex environments with unbound domains, in particular, velocity-modulating environments and the effect of local gradients.
  • Gating and tunable confinement of active colloids within patterned environments
    Item type: Journal Article
    van Baalen, Carolina; Ketzetzi, Stefania; Tintor, Anushka; et al. (2025)
    Soft Matter
    Active colloidal particles typically exhibit a pronounced affinity for accumulating and being captured at boundaries. Here, we engineer long-range repulsive interactions between colloids that self-propel under an electric field and patterned obstacles. As a result of these interactions, particles turn away from obstacles and avoid accumulation. We show that by tuning the applied field frequency, we precisely and rapidly control the effective size of the obstacles and therefore modulate the particle approach distance. This feature allows us to achieve gating and tunable confinement of our active particles whereby they can access regions between obstacles depending on the applied field. Our work provides a versatile means to directly control confinement and organization, paving the way towards applications such as sorting particles based on motility or localizing active particles on demand.
Publications 1 - 3 of 3