اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدNanomorphology of Annealed P3HS and P3HS:PCBM Films for OPV Applications
88
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Atomic Force Microscopy (AFM) and Grazing Incidence X-Ray Diffraction (GI-XRD) are used to characterize the nanomorphology of spin-coated low (LMW, Mn = 12 kg/mol, regioregularity RR = 84%) and high (HMW, Mn = 39 kg/mol, RR = 98%) molecular weight poly(3-hexylselenophene) (P3HS) films and blend films of P3HS with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), before and after thermal annealing at 250 {deg}C.
قيم البحث
اقرأ أيضاً
We present detailed systematic studies of structural transformations in thin liquid crystal films with the smectic-C to hexatic phase transition. For the first time all possible structures reported in the literature are observed for one material (5 O
.6) at the variation of temperature and thickness. In unusual modulated structures the equilibrium period of stripes is twice with respect to the domain size. We interpret these patterns in the frame work of phenomenological Landau type theory, as equilibrium phenomena produced by a natural geometric frustration in a system having spontaneous splay distortion.
We develop general methods to calculate the mobilities of extended bodies in (or associated with) membranes and films. We demonstrate a striking difference between in-plane motion of rod-like inclusions and the corresponding case of bulk (three-dimen
sional) fluids: for rotations and motion perpendicular to the rod axis, we find purely local drag, in which the drag coefficient is purely algebraic in the rod dimensions. These results, as well as the calculational methods are applicable to such problems as the diffusion of objects in or associated with Langmuir films and lipid membranes. The methods can also be simply extended to treat viscoelastic systems.
I review single-molecule experiments (SME) in biological physics. Recent technological developments have provided the tools to design and build scientific instruments of high enough sensitivity and precision to manipulate and visualize individual mol
ecules and measure microscopic forces. Using SME it is possible to: manipulate molecules one at a time and measure distributions describing molecular properties; characterize the kinetics of biomolecular reactions and; detect molecular intermediates. SME provide the additional information about thermodynamics and kinetics of biomolecular processes. This complements information obtained in traditional bulk assays. In SME it is also possible to measure small energies and detect large Brownian deviations in biomolecular reactions, thereby offering new methods and systems to scrutinize the basic foundations of statistical mechanics. This review is written at a very introductory level emphasizing the importance of SME to scientists interested in knowing the common playground of ideas and the interdisciplinary topics accessible by these techniques. The review discusses SME from an experimental perspective, first exposing the most common experimental methodologies and later presenting various molecular systems where such techniques have been applied. I briefly discuss experimental techniques such as atomic-force microscopy (AFM), laser optical tweezers (LOT), magnetic tweezers (MT), biomembrane force probe (BFP) and single-molecule fluorescence (SMF). I then present several applications of SME to the study of nucleic acids (DNA, RNA and DNA condensation), proteins (protein-protein interactions, protein folding and molecular motors). Finally, I discuss applications of SME to the study of the nonequilibrium thermodynamics of small systems and the experimental verification of fluctuation theorems. I conclude with a discussion of open questions and future perspectives.
We investigate the relaxation behavior of thin films of a polyamide random copolymer, PA66/6I, with various film thicknesses using dielectric relaxation spectroscopy. Two dielectric signals are observed at high temperatures, the $alpha$-process and t
he relaxation process due to electrode polarization (the EP-process). The relaxation time of the EP-process has a Vogel-Fulcher-Tammann type of temperature dependence, and the glass transition temperature, $T_{rm g}$, evaluated from the EP-process agrees very well with the $T_{rm g}$ determined from the thermal measurements. The fragility index derived from the EP-process increases with decreasing film thickness. The relaxation time and the dielectric relaxation strength of the EP-process are described by a linear function of the film thickness $d$ for large values of $d$, which can be regarded as experimental evidence for the validity of attributing the observed signal to the EP-process. Furthermore, there is distinct deviation from this linear law for thicknesses smaller than a critical value. This deviation observed in thinner films is associated with an increase in the mobility and/or diffusion constant of the charge carriers responsible for the EP-process. The $alpha$-process is located in a high frequency region than the EP-process at high temperatures, but merges with the EP-process at lower temperatures near the glass transition region. The thickness dependence of the relaxation time of the $alpha$-process is different from that of the EP-process. This suggests that there is decoupling between the segmental motion of the polymers and the translational motion of the charge carriers in confinement.
A theory of photoinduced directed bending of non-crystalline molecular films is presented. Our approach is based on elastic deformation of the film due to interaction between molecules ordered through polarized light irradiation. The shape of illumin
ated film is obtained in the frame of the nonlinear elasticity theory. It is shown that the shape and the curvature of the film depend on the polarization and intensity of the light. The curvature of an irradiated film is a non-monotonic function of the extinction coefficient.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
