We study the effect of a random Flory-Huggins parameter in a symmetric diblock copolymer melt which is expected to occur in a copolymer where one block is near its structural glass transition. In the clean limit the microphase segregation between the two blocks causes a weak, fluctuation induced first order transition to a lamellar state. Using a renormalization group approach combined with the replica trick to treat the quenched disorder, we show that beyond a critical disorder strength, which depends on the length of the polymer chain, the character of the transition is changed. The system becomes dominated by strong randomness and a glassy rather than an ordered lamellar state occurs. A renormalization of the effective disorder distribution leads to nonlocal disorder correlations that reflect strong compositional fluctuation on the scale of the radius of gyration of the polymer chains. The reason for this behavior is shown to be the chain length dependent role of critical fluctuations, which are less important for shorter chains and become increasingly more relevant as the polymer length increases and the clean first order transition becomes weaker.
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http://dx.doi.org/10.1103/PhysRevE.72.011806 | DOI Listing |
Phys Chem Chem Phys
January 2025
State Key Lab of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Mechanoresponsive colloidal photonic crystals embedded in elastic solid matrices exhibit tunable optical properties under mechanical force, showing great potential for various applications. However, the response of colloidal crystals embedded in a liquid matrix remains largely unexplored. In this study, we investigate the structural and optical transitions of colloidal crystals composed of particles suspended in a liquid oligomer under pressing and shear forces.
View Article and Find Full Text PDFDalton Trans
January 2025
School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212100, Jiangsu, China.
Five alkali metal manganese(III) fluorophosphates, KMn(POF)F (I), RbMn(POF)F (II), RbMn(POF)(PO)F (III), RbMn(POF)(PO)F (IV), and CsMn(POF)F (V), were successfully synthesized using a hydrothermal method. The monofluorophosphate anion (POF) groups work as "chemical scissors" to promote low-dimensional spin structures with the aid of alkali metal cations. I and II had an = 2 uniform chain structure formed by corner-sharing -MnOF octahedra.
View Article and Find Full Text PDFSoft Matter
January 2025
Department of Physics, Central University of Karnataka, Kadaganchi, Kalaburagi, Karnataka-585367, India.
The isomerization kinetics of a liquid crystalline azobenzene dimer, comprising cyanoazobenzene and naphthalene (NAZ6), were investigated at the air-water interface. The Langmuir monolayers of NAZ6 in both its and states were analyzed using surface manometry techniques. The results revealed that NAZ6 molecules in the -state displayed the coexistence of a disordered liquid-expanded phase and an ordered liquid-condensed phase, whereas no such phase transition was observed in the -state.
View Article and Find Full Text PDFSoft Matter
January 2025
Departamento de Estructura de la Materia, Física Térmica y Electrónica, Universidad Complutense de Madrid, 28040 Madrid, Spain.
The effect of gravity on the collective motion of living microswimmers, such as bacteria and micro-algae, is pivotal to unravel not only bio-convection patterns but also the settling of bacterial biofilms on solid surfaces. In this work, we investigate suspensions of microswimmers under the influence of a gravitational field and hydrodynamics, simulated the dissipative particle dynamics (DPD) coarse-grained model. We first study the collective sedimentation of passive colloids and microswimmers of the puller and pusher types upon increasing the imposed gravitational field and compare them with previous results.
View Article and Find Full Text PDFAnn Bot
January 2025
Agassiz Research and Development Centre, Agriculture and Agri-food Canada, Agassiz, British Columbia, Canada.
Background And Aims: Genome size varies by orders of magnitude across land plants, and the factors driving evolutionary increases and decreases in genome size vary across lineages. Bryophytes have the smallest genomes relative to other land plants and there is growing evidence for frequent whole genome duplication (WGD) across the lineage. However, the broad patterns of genome size, chromosome number, and WGD have yet to be characterized across bryophytes in a phylogenetic context.
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