Chain Order Research Articles

Aging‐induced structural relaxation in cornstarch plasticized with urea and glycerol

AbstractIn present work structural properties and aging of thermoplastic starches prepared by plasticization of cornstarch with urea, glycerol and their mixtures are studied using solid‐state1H NMR and13C NMR spectroscopy and WAXS measurements. Broad line1H NMR spectra reveal phase separation of plasticizers during aging of the samples with the same or higher relative amount of glycerol than the amount of urea. Glycerol in the TPS samples induces motion of starch chain segments, the mobility of which depends on the relative amount of glycerol. At the scale of nm, formation of B‐type crystallites in the samples containing glycerol and also of single‐helical crystallinity in all samples is observed during one‐year aging through cross‐polarization magic angle spinning13C NMR spectra. Urea, when used as the sole plasticizer, prevents the ordering of starch chains in B‐type crystallites. WAXS diffractograms show that regular crystals do not form in any of the samples.

Serotonin Alters the Phase Equilibrium of a Ternary Mixture of Phospholipids and Cholesterol.

Unsaturated and saturated phospholipids tend to laterally segregate, especially in the presence of cholesterol. Small molecules such as neurotransmitters, toxins, drugs etc. possibly modulate this lateral segregation. The small aromatic neurotransmitter serotonin (5-HT) has been found to bind to membranes. We studied the lipid structure and packing of a ternary membrane mixture consisting of palmitoyl-oleoyl-phosphatidylcholine, palmitoyl-sphingomyelin, and cholesterol at a molar ratio of 4/4/2 in the absence and in the presence of 5-HT, using a combination of solid-state 2H NMR, atomic force microscopy, and atomistic molecular dynamics (MD) simulations. Both NMR and MD report formation of a liquid ordered (Lo) and a liquid disordered (Ld) phase coexistence with small domains. Lipid exchange between the domains was fast such that single component 2H NMR spectra are detected over a wide temperature range. A drastic restructuring of the domains was induced when 5-HT is added to the membranes at a 9 mol% concentration relative to the lipids. 2H NMR spectra of all components of the mixture showed two prominent contributions indicative of molecules of the same kind residing both in the disordered and the ordered phase. Compared to the data in the absence of 5-HT, the lipid chain order in the disordered phase was further decreased in the presence of 5-HT. Likewise, addition of serotonin increased lipid chain order within the ordered phase. These characteristic lipid chain order changes were confirmed by MD simulations. The 5-HT-induced larger difference in lipid chain order results in more pronounced differences in the hydrophobic thickness of the individual membrane domains. The correspondingly enlarged hydrophobic mismatch between ordered and disordered phases is assumed to increase the line tension at the domain boundary, which drives the system into formation of larger size domains. These results not only demonstrate that small membrane binding molecules such as neurotransmitters have a profound impact on essential membrane properties. It also suggests a mechanism by which the interaction of small molecules with membranes can influence the function of membrane proteins and non-cognate receptors. Altered membrane properties may modify lateral sorting of membrane protein, membrane protein conformation, and thus influence their function as suspected for neurotransmitters, local anesthetics, and other small drug molecules.

Soft Matter Mechanics and the Mechanisms Underpinning the Infrared Vision of Snakes

Summary Pit-bearing snakes (vipers, pythons, and boas) have the extraordinary ability to “see” and accurately locate their prey and predators in total darkness. These animals use the infrared radiation emanating from objects that are warmer relative to the background environment to form a thermal image. Although enormous progress has been made to identify the key physiological features that enable the infrared vision of these snakes and a few other animals, the precise thermoelectric transduction mechanism that mediates the conversion of infrared heat to processable electrical signals has remained elusive. In this work, we quantitatively outline how cells in the snake's pit membrane organ act as apparent pyroelectric materials and convert infrared radiation into electrical signals. Despite the exceptional simplicity of our proposed mechanism and model, we are able to explain many central experimental results pertaining to the transduction process.

Substrate-Dependent Study of Chain Orientation and Order in Alkylphosphonic Acid Self-Assembled Monolayers for ALD Blocking.

For years, many efforts in area selective atomic layer deposition (AS-ALD) have focused on trying to achieve high-quality self-assembled monolayers (SAMs), which have been shown by a number of studies to be effective for blocking deposition. Herein, we show that in some cases where a densely packed SAM is not formed, significant ALD inhibition may still be realized. The formation of octadecylphosphonic acid (ODPA) SAMs was evaluated on four metal substrates: Cu, Co, W, and Ru. The molecular orientation, chain packing, and relative surface coverage were evaluated using near-edge X-ray absorption fine structure (NEXAFS), Fourier transform infrared (FTIR) spectroscopy, and electrochemical impedance spectroscopy (EIS). ODPA SAMs formed on Co, Cu, and W showed strong angular dependence of the NEXAFS signal whereas ODPA on Ru did not, suggesting a disordered layer was formed on Ru. Additionally, EIS and FTIR spectroscopy confirmed that Co and Cu form densely packed, "crystal-like" SAMs whereas Ru and W form less dense monolayers, a surprising result since W-ODPA was previously shown to inhibit the ALD of ZnO and Al2O3 best among all the substrates. This work suggests that multiple factors play a role in SAM-based AS-ALD, not just the SAM quality. Therefore, metrological averaging techniques (e.g., WCA and FTIR spectroscopy) commonly used for evaluating SAMs to predict their suitability for ALD inhibition should be supplemented by more atomically sensitive methods. Finally, it highlights important considerations for describing the mechanism of SAM-based selective ALD.

Operation strategies with respect to insurance subsidy optimization for online retailers dealing with large items

In order to promote sales, some online platforms put forward freight insurance. However, as we know, only two cases are provided by online retailers in current online platforms. One is no freight insurance subsidy, the other is full freight insurance subsidy covered all goods. As the sale of large items in online platforms is more difficult than other merchandise, we focus on the freight insurance of selling large items online in the paper. The cases of freight insurance subsidy for partial goods and partial freight insurance subsidy in supply chain are introduced. Freight insurance subsidy for partial goods and partial freight insurance subsidy both contain a case of no freight insurance subsidy and a case of full freight insurance subsidy covered all goods. To study these two new types of freight insurance, we improve a new form of newsvendor model and introduce new demand functions, based on them, we focus on researching the problems of order, insurance and marketing in upstream and downstream two-echelon supply chains. Through these studies, we can get operation strategies that include order, insurance and marketing strategies with respect to optimal insurance subsidies, so that help online retailers sell large items and make more profits. Lastly, we provide two examples to illustrate the validity of the proposed methods.

General metaheuristic-based methodology for computation and decomposition of LMPs

Locational marginal prices (LMPs) are economic signals paramount to the deliberations, policy designs, and planning judgments of most electricity markets. This paper presents a general metaheuristic-based methodology applied in the scope of two subproblems to compute and decompose the LMPs considering the incorporation of a distributed slack bus model in the power flow formulation. The deterministic core of the methodology is governed by a process of sequential setting of maximum number of metaheuristic iterations based on load disharmony indices (LDIs) in the context of the initial subproblem. The metaheuristic crux of the methodology is anchored in a random initialization strategy based on time-traveling parameters in the environment of both subproblems. In the introductory arrangement of the optimization sequence, the chain order of the operating horizon periods is defined based on the LDIs. Due to its notorious merits and the breadth of its applications in power system problems, a particle swarm optimization (PSO) algorithm model is used to solve the mentioned subproblems. For the practical purposes of this paper, in the PSO algorithm model instance the particle coordinates are adopted as time-traveling metaheuristic parameters. Numerical simulations on a 3-bus system and on the IEEE 30-bus test system corroborate the efficiency and adequacy of the proposed methodology.

Random copolymerization of regiorandom polythiophene to improve planarity, aggregation and hole-transport

Charge transport in semiconducting conjugated polymers mainly devolves on the solid-state ordering of polymer chains with respect to its packing and orientation. Therefore, controlling the inter- and intra-molecular interactions of polymer chains is vital for achieving high performance conjugated polymers for electronic applications. Herein, by a macromolecular design scheme, we optimized the microstructure of a regiorandom poly (thiophene) copolymer for efficient charge transport. By introducing side chain-free phenyl and pyridyl units into the backbone, we achieved regiorandom polymers possessing improved inter- and intra-molecular interactions with a much closer π-π molecular stacking and a larger size of crystallites. Improved charge carrier motion and transport in both vertical and horizontal directions were revealed when the resulting phenyl and pyridyl substituted polymers were applied as hole-transporting materials in organic field-effect transistors, diode-like space-charge-limited current devices, and perovskite solar cells. Particularly, the pyridyl substituted polymer exhibited more than two times higher charge carrier mobilities in the above mentioned device configurations compared with the pristine regiorandom poly (thiophene).

Polycation-Anionic Lipid Membrane Interactions.

Natural or synthetic polycations are used as biocides or as drug/gene carriers. Understanding the interactions between these macromolecules and cell membranes at the molecular level is therefore of great importance for the design of effective polymer biocides or biocompatible polycation-based delivery systems. Until now, details of the processes at the interface between polycations and biological systems have not been fully recognized. In this study, we consider the effect of strong polycations with quaternary ammonium groups on the properties of anionic lipid membranes that we use as a model system for protein-free cell membranes. For this purpose, we employed experimental measurements and atomic-scale molecular dynamics (MD) simulations. MD simulations reveal that the polycations are strongly hydrated in the aqueous phase and do not lose the water shell after adsorption at the bilayer surface. As a result of strong hydration, the polymer chains reside at the phospholipid headgroup and do not penetrate to the acyl chain region. The polycation adsorption involves the formation of anionic lipid-rich domains, and the density of anionic lipids in these domains depends on the length of the polycation chain. We observed the accumulation of anionic lipids only in the leaflet interacting with the polymer, which leads to the formation of compositionally asymmetric domains. Asymmetric adsorption of the polycation on only one leaflet of the anionic membrane strongly affects the membrane properties in the polycation–membrane contact areas: (i) anionic lipid accumulates in the region near the adsorbed polymer, (ii) acyl chain ordering and lipid packing are reduced, which results in a decrease in the thickness of the bilayer, and (iii) polycation–anionic membrane interactions are strongly influenced by the presence and concentration of salt. Our results provide an atomic-scale description of the interactions of polycations with anionic lipid bilayers and are fully supported by the experimental data. The outcomes are important for understanding the correlation of the structure of polycations with their activity on biomembranes.

Injectability of Thermosensitive, Low-Concentrated Chitosan Colloids as Flow Phenomenon through the Capillary under High Shear Rate Conditions.

Low-concentrated colloidal chitosan systems undergoing a thermally induced sol–gel phase transition are willingly studied due to their potential use as minimally invasive injectable scaffolds. Nevertheless, instrumental injectability tests to determine their clinical utility are rarely performed. The aim of this work was to analyze the flow phenomenon of thermosensitive chitosan systems with the addition of disodium β-glycerophosphate through hypodermic needles. Injectability tests were performed using a texture analyzer and hypodermic needles in the sizes 14G–25G. The rheological properties were determined by the flow curve, three-interval thixotropy test (3ITT), and Cox–Merz rule. It was found that reducing the needle diameter and increasing its length and the crosshead speed increased the injection forces. It was claimed that under the considered flow conditions, there was no need to take into account the viscoelastic properties of the medium, and the model used to predict the injection force, based solely on the shear-thinning nature of the experimental material, showed very good agreement with the experimental data in the shear rate range of 200–55,000 s−1. It was observed that the increase in the shear rate value led to macroscopic structural changes of the chitosan sol caused by the disentangling and ordering of the polysaccharide chains along the shear field.

Swift heavy ion irradiation induced negative differential resistance and transport of charge carriers in conducting polymer-metal oxide hybrids

An intriguing phenomenon of the negative differential resistance (NDR) in conducting polymer-metal oxide hybrids is manifested upon measuring the In-situ current-voltage characteristics. Anomalous evolution of low current state leading to the electrical bistability has also been observed as an induced effect at low ion irradiation doses and explained by invoking ordering of the polymer chains and electric-field induced charge transfer mechanisms. Later, a disorder leading to damage is observed at higher doses by the diffusion of irradiation-induced electrically active free radicals and defect centers within the active region of the device. This leads to the device into a high current state of electrical bistability. Further, the observed NDR is attributed to the tunneling of carriers along with transient charging of molecular chains by trapping of charge carriers at the heterojunction interfaces induced by ion irradiation. It is further confirmed by anomalous response of voltage shifting in the conductance response upon incremented doses of irradiation. Efforts are envisaged to understand the processes of irradiation interactions and their influences on the transport of charge carriers by fitting experimental data using various conduction models such as Ohmic conduction, space-charge-limited conduction (SCLC), and trap-assisted SCLC. Thus, such low-cost and simple design devices have lots of potential applications for radiation harsh environments and could be easily integrated into the existing silicon-based technology.

Binding of warfarin differently affects the thermal behavior and chain packing of anionic, zwitterionic and cationic lipid membranes

Warfarin is a coumarin derivative drug widely used for its anticoagulant properties. The interaction of warfarin with fully hydrated lipid bilayers has been studied by combining differential scanning calorimetry, spectrophotometry, electron spin resonance of chain-labelled lipids and molecular docking. Bilayers formed by lipids with different chemico-physical properties were considered, namely dimyristoyl-phosphatidylcholine (DMPC), dimyristoyl-phosphatidylglycerol (DMPG), and dioleoyltrimethyl-ammoniumpropane (DOTAP). We observed in all cases the binding of warfarin in proximity of the surface of the bilayers, leading to a variety of distinct effects on key molecular properties of the membranes. The drug associates with the lipid bilayers in the deprotonated open chain form, with an association constant similar for DMPC and DMPG (1.27·104 and 2.82·104 M−1, respectively) and lower for DOTAP (0.46·104 M−1). In DMPC bilayers, which are zwitterionic and with saturated symmetrical chains, warfarin at 10 mol% suppresses the pre-transition, slightly stabilizes the fluid state and reduces the cooperativity of the main transition. Moreover, it alters the lateral packing density of the chain segments close to the polar/apolar interface at any temperature through the gel phase. In anionic DMPG bilayers, the drug slightly perturbs the thermotropic phase behavior, and at 10 mol% markedly loosens the compact gel phase packing of the first chain segments. In cationic DOTAP bilayers, possessing unsaturated acyl chains, the drug induces a slightly higher degree of order and motional restriction in the outer hydrocarbon region in the frozen state. In all cases, as a surface adsorbed molecule, warfarin does not affect the segmental chain order and dynamics for temperatures in the fluid phase. The overall results provide an outline of the action of warfarin on membranes formed by lipids of different types.

Transmembrane potential of physiologically relevant model membranes: Effects of membrane asymmetry.

Transmembrane potential difference (Vm) plays important roles in regulating various biological processes. At the macro level, Vm can be experimentally measured or calculated using the Nernst or Goldman-Hodgkin-Katz equation. However, the atomic details responsible for its generation and impact on protein and lipid dynamics still need to be further elucidated. In this work, we performed a series of all-atom molecular dynamics (MD) simulations of symmetric model membranes of various lipid compositions and cation contents to evaluate the relationship between membrane asymmetry and Vm. Specifically, we studied the impact of the asymmetric distribution of POPS (1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-l-serine), PIP2 (phosphatidylinositol 4,5-bisphosphate), as well as Na+ and K+ on Vm using atomically detailed MD simulations of symmetric model membranes. The results suggest that, for an asymmetric POPC-POPC/POPS bilayer in the presence of NaCl, the presence of the monovalent anionic lipid POPS in the inner leaflet polarizes the membrane (ΔVm < 0). Intriguingly, replacing a third of the POPS lipids by the polyvalent anionic signaling lipid PIP2 counteracts this effect, resulting in a smaller negative membrane potential. We also found that replacing Na+ ions in the inner region by K+ depolarizes the membrane (ΔVm > 0). These divergent effects arise from variations in the strength of cation-lipid interactions and are correlated with changes in lipid chain order and head-group orientation.

A molecular dynamics study of epitaxy-induced chain orientation and ordering of isotactic polypropylene

Phase selective nucleation of single chain isotactic polypropylene (iPP) into specific crystalline polymorphs is enabled by heterogeneous nucleating agents. Molecular dynamics simulations were used to investigate the ordering of isolated iPP chains over ideal (α-iPP and β-iPP) and commercial (triphenodithiazine, TPDT) heterogeneous nucleating surfaces during the early stages of nucleation. The ordering of an iPP chain during nucleation is analyzed by following the evolution of helix conformations, chiral order parameter, chain orientation and radius of gyration. The results show that α-iPP and β-iPP have a greater tendency to select chirality. However, TPDT is the most efficient in orienting the chain because of bulky phenyl groups on its surface. Based on helix evolution and segment orientation, early-stage ordering of iPP on crystalline surfaces is proposed to proceed by two different routes; (i) CTEH (coil-to-extended helix) where helix formation and segment orientation occur simultaneously, and (ii) CTEC (coil-to-extended coil) where segment orientation occurs without helix formation, thus indicating multistage nucleation through an intermediate mesomorphic phase. Whereas, CTEC is the predominant ordering route on TPDT, both CTEC and CTEH occur simultaneously on α-iPP and β-iPP, emphasizing the important role of epitaxy in early-stage ordering during crystallization.

Molecular Insight into the Mutual Interactions of Two Transmembrane Domains of Human Glycine Receptor (TM23-GlyR), with the Lipid Bilayers

Appearing as a computational microscope, MD simulation can ‘zoom in’ to atomic resolution to assess detailed interactions of a membrane protein with its surrounding lipids, which play important roles in the stability and function of such proteins. This study has employed the molecular dynamics (MD) simulations, to determine the effect of added DMPC or DMTAP molecules on the structure of DPPC bilayer, and also to characterize the mutual interactions of TM23-GlyR (The second and third transmembrane domains of glycine receptor), with the pure and mixed lipid bilayers. Structural properties of DPPC bilayer, namely the order of acyl chains and the area per lipid, were affected by cationic DMTAP and zwitterionic DMPC lipids, in completely reverse ways. In the case of the mutual interactions of lipid molecules and TM23-GlyR, the cationic DMTAP lipids showed greater impact on the structural properties of this protein. On the other hand, TM23-GlyR caused clear increase in the lipid chain order, due to the positive hydrophobic mismatch. In total, this study could shed light on the effect of lipid force field, chain length, and the head group charge and size, on the lipid-protein interplay.

Local Disorder Facilitates Chain Stretching in Crowded Polymer Brushes.

Intermolecular crowding of densely tethered polymers promotes chain extension and anisotropy that induces many unique properties. In this study, we used conformation-sensitive infrared spectroscopy to determine that chain extension in a polymer brush is associated with local conformation rearrangements, i.e., contraction of side groups and increased proportion of gauche twists in the backbone, which served to increase molecular disorder at or below the segmental scale. This conformational transition points to a particular molecular mechanism for chain extension in densely tethered polymers, wherein increased local disorder facilitates global chain ordering (i.e., chain extension) and therefore supplements our current understanding of chain orientation at a molecular level.

Pathway of orientational symmetry breaking in crystallization of short n-alkane droplets: A molecular dynamics study.

We carry out molecular dynamics simulations by using an all-atom model to study the nucleation and crystallization of n-alkane droplets under three-dimensional and quasi-two-dimensional conditions. We focus on the development of orientational order of chains from a random state to a neatly ordered one. Two new methods, the map of symmetry breaking and the information entropy of chain orientations, are introduced to characterize the emerge and remelting phenomena of a primary nucleus at the early stage of crystallization. Stepwise nucleation, as well as the surface induced nucleation, of large droplets is observed. We elucidate the kinetic process of the formation of a primary nucleus and the rearrangement of every single molecule involved in a primary nucleus. We found that density fluctuation and orientational preordering are coupled together and occur simultaneously in nucleation. Our results show the pathway of orientational symmetry breaking in the crystallization of n-alkane droplets that are heuristic for the deeper understanding of the crystallization in more complex molecules such as polymers.

Some thermodynamic effects of varying nonpolar surfaces in protein-ligand interactions.

Understanding how making structural changes in small molecules affects their binding affinities for targeted proteins is central to improving strategies for rational drug design. To assess the effects of varying the nature of nonpolar groups upon binding entropies and enthalpies, we designed and prepared a set of Grb2-SH2 domain ligands, Ac-pTyr-Ac6c-Asn-(CH2)n-R, in which the size and electrostatic nature of R groups at the pTyr+3 site were varied. The complexes of these ligands with the Grb2-SH2 domain were evaluated in a series of studies in which the binding thermodynamics were determined using isothermal titration calorimetry, and binding interactions were examined in crystallographic studies of two different complexes. Notably, adding nonpolar groups to the pTyr+3 site leads to higher binding affinities, but the magnitude and energetic origins of these effects vary with the nature of the R substituent. For example, enhancements to binding affinities using aliphatic R groups are driven by more favorable changes in binding entropies, whereas aryl R groups improve binding free energies through a combination of more favorable changes in binding enthalpies and entropies. However, enthalpy/entropy compensation plays a significant role in these associations and mitigates against any significant variation in binding free energies, which vary by only 0.8kcal•mol-1, with changes in the electrostatic nature and size of the R group. Crystallographic studies show that differences in ΔG° or ΔH° correlate with buried nonpolar surface area, but they do not correlate with the total number of polar or van der Waals contacts. The relative number of ordered water molecules and relative order in the side chains at pTyr+3 correlate with differences in -TΔS°. Overall, these studies show that burial of nonpolar surface can lead to enhanced binding affinities arising from dominating entropy- or enthalpy-driven hydrophobic effects, depending upon the electrostatic nature of the apolar R group.

Membrane interactions of the anuran antimicrobial peptide HSP1-NH2: Different aspects of the association to anionic and zwitterionic biomimetic systems

Studies have suggested that antimicrobial peptides act by different mechanisms, such as micellisation, self-assembly of nanostructures and pore formation on the membrane surface. This work presents an extensive investigation of the membrane interactions of the 14 amino-acid antimicrobial peptide hylaseptin P1-NH2 (HSP1-NH2), derived from the tree-frog Hyla punctata, which has stronger antifungal than antibacterial potential. Biophysical and structural analyses were performed and the correlated results were used to describe in detail the interactions of HSP1-NH2 with zwitterionic and anionic detergent micelles and phospholipid vesicles. HSP1-NH2 presents similar well-defined helical conformations in both zwitterionic and anionic micelles, although NMR spectroscopy revealed important structural differences in the peptide N-terminus. 2H exchange experiments of HSP1-NH2 indicated the insertion of the most N-terminal residues (1–3) in the DPC-d38 micelles. A higher enthalpic contribution was verified for the interaction of the peptide with anionic vesicles in comparison with zwitterionic vesicles. The pore formation ability of HSP1-NH2 (examined by dye release assays) and its effect on the size and surface charge as well as on the lipid acyl chain ordering (evaluated by Fourier-transform infrared spectroscopy) of anionic phospholipid vesicles showed membrane disruption even at low peptide-to-phospholipid ratios, and the effect increases proportionately to the peptide concentration. On the other hand, these biophysical investigations showed that a critical peptide-to-phospholipid ratio around 0.6 is essential for promoting disruption of zwitterionic membranes. In conclusion, this study demonstrates that the binding process of the antimicrobial HSP1-NH2 peptide depends on the membrane composition and peptide concentration.

Roles of histidine charge and cardiolipin in membrane disruption by antimicrobial peptides Gaduscidin-1 and Gaduscidin-2

Gad-1 and Gad-2 are helical, histidine-rich antimicrobial peptides (AMPs) from paralogous genes in cod. 15N and 2H solid state nuclear magnetic resonance (NMR) were used to characterize their lipid-bound structures and lipid interactions. Gad-1 was found to position in-plane in POPC: POPG bilayers. Gad-1 displayed greater effects than Gad-2 on lipid acyl chain order of POPE: POPG and POPE: POPG: CL bilayers, in keeping with its greater activity against E. coli. The effect of Gad-1 and Gad-2 on lipid bilayer order was only weakly affected by changes in pH, and hence changes in histidine charge. This was somewhat surprising for Gad-2 as this peptide's biological activity has been shown to be greater at low pH and thus the finding may point to the existence of functional interactions with non-lipid components of bacteria. The incorporation of cardiolipin into POPE: POPG bilayers in such a way as to preserve the overall charge of the bilayers did not alter Gad-1's effects on lipid acyl chain order parameters, which report on motions on the 10−5 s timescale. When cardiolipin and Gad-1 were both present, there were subtle changes on membrane dynamics at other timescales.

Graphene assisting magnetic alignment of a high-performance semiconducting polymer for improved carrier transport

We report the fabrication of large-area highly aligned films of a naphthalene dicarboximide-based copolymer P(NDI2OD-T2) via solvent vapor annealing of as-spun films under a high magnetic field. Structural characterization reveals that the incorporation of a small amount of graphene nanosheets via solution mixing remarkably improves the degree of chain alignment and ordering of the semiconducting polymers. Field-effect transistors based on the magnetically aligned polymer/graphene composites exhibit a dramatic enhancement of electron mobility as well as extraordinarily high mobility anisotropy of 81, compared to pristine P(NDI2OD-T2)-based devices. We further proposed a mechanism to explain the enhancement of molecular orientation and charge transport, which is based on the assembling of polymer aggregates on the π-plane of graphene to facilitate magnetic alignment.