title: Chiral self-assembly of helical particles.
abstract: The shape of the building blocks plays a crucial role in directing self-assembly towards desired architectures. Out of the many different shapes, the helix has a unique position. Helical structures are ubiquitous in nature and a helical shape is exhibited by the most important biopolymers like polynucleotides, polypeptides and polysaccharides as well as by cellular organelles like flagella. Helical particles can self-assemble into chiral superstructures, which may have a variety of applications, e.g. as photonic (meta)materials. However, a clear and definite understanding of these structures has not been entirely achieved yet. We have recently undertaken an extensive investigation on the phase behaviour of hard helical particles, using numerical simulations and classical density functional theory. Here we present a detailed study of the phase diagram of hard helices as a function of their morphology. This includes a variety of liquid-crystal phases, with different degrees of orientational and positional ordering. We show how, by tuning the helix parameters, it is possible to control the organization of the system. Starting from slender helices, whose phase behaviour is similar to that of rodlike particles, an increase in curliness leads to the onset of azimuthal correlations between the particles and the formation of phases specific to helices. These phases feature a new kind of screw order, of which there is experimental evidence in colloidal suspensions of helical flagella.
authors.affiliation: Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca' Foscari di Venezia, Campus Scientifico, Edificio Alfa, via Torino 155, 30170 Venezia Mestre, Italy.
authors.forename: Hima Bindu
authors.initials: HB
authors.lastname: Kolli
authors.affiliation: Departamento de Física Teórica de la Materia Condensada, Instituto de Física de la Materia Condensada (IFIMAC) and Instituto de Ciencias de Materiales "Nicolás Cabreras", Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain. giorgio.cinacchi@uam.es.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Cinacchi
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Padova, via F. Marzolo 1, 35131 Padova, Italy. alberta.ferrarini@unipd.it.
authors.forename: Alberta
authors.initials: A
authors.lastname: Ferrarini
authors.affiliation: Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca' Foscari di Venezia, Campus Scientifico, Edificio Alfa, via Torino 155, 30170 Venezia Mestre, Italy. achille.giacometti@unive.it.
authors.forename: Achille
authors.initials: A
authors.lastname: Giacometti
mesh_terms: D005407:Flagella / Q000737:chemistry; D050866:Liquid Crystals / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D010455:Peptides / Q000737:chemistry; D044367:Phase Transition; D017785:Photons; D011119:Polynucleotides / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry
chemical_list: D010455:Peptides; D011119:Polynucleotides; D011134:Polysaccharides