Degree Of Phase Separation Research Articles

Solution‐Doped Donor–Acceptor Copolymers Based on Diketopyrrolopyrrole and 3, 3′‐Bis (2‐(2‐(2‐Methoxyethoxy) Ethoxy) ethoxy)‐2, 2′‐Bithiophene Exhibiting Outstanding Thermoelectric Power Factors with p‐Dopants

AbstractThe design of polymeric semiconductors exhibiting high electrical conductivity (σ) and thermoelectric power factor (PF) will be vital for flexible large‐area electronics. In this work, four polymers based on diketopyrrolopyrrole (DPP), 2,3‐dihydrothieno[3,4‐b][1,4]dioxine (EDOT), thieno[3,2‐b]thiophene (TT), and 3, 3′‐bis (2‐(2‐(2‐methoxyethoxy) ethoxy) ethoxy)‐2, 2′‐bithiophene (MEET) are investigated as side‐chains, with the MEET polymers newly synthesized for this study. These polymers are systematically doped with tetrafluorotetracyanoquinodimethane ( F4TCNQ), CF3SO3H, and the synthesized dopant Cp(CN)3‐(COOMe)3, differing in geometry and electron affinity. The DPP‐EDOT‐based polymer containing MEET as side‐chains exhibits the highest conductivity (σ) ≈700 S cm−1 in this series with the acidic dopant (CF3SO3H). This polymer also shows the lowest oxidation potential by cyclic voltammetry (CV), the strongest intermolecular interactions evidenced by differential scanning calorimetry (DSC), and has the most oxygen‐based functionality for possible hydrogen bonding and ionic screening. Other polymers exhibit high σ ≈300–500 S cm−1 and power factor up to 300 µW m−1 K−2. The mechanism of conductivity is predominantly electronic, as validated by time‐dependent conductance studies and transient thermo voltage monitoring over time, including for those doped with the acid. These materials maintain significant thermal stability and air stability over ≈6 weeks. Density functional theory calculations reveal molecular geometries and inform about frontier energy levels. Raman spectroscopy, in conjunction with scanning electron microscopy (SEM‐EDS) and x‐ray diffraction, provides insight into the solid‐state microstructure and degree of phase separation of the doped polymer films. Infrared spectroscopy enables this study to further quantify the degree of charge transfer from polymer to dopant.

Effect of Tacticity Sequence of the Poly(N-isopropylacrylamide) Oligomer on Phase Transition Behavior in Aqueous Solution.

The tacticity of poly(N-isopropylacrylamide) (PNIPAM) has a strong impact on the lower critical solution temperature (LCST) in aqueous solution. The sequence of meso diads (m) and racemo diads (r) further contributes to such an effect. In this work, the phase transition behaviors of poly(N-isopropylacrylamide) pentamers with four kinds of sequences, i.e., rrmm, rmmr, mrrm, and rmrm, in water were studied applying replica exchange molecular dynamics with a modified OPLS/AA force field. The difference in local component concentration in the system was used as an order parameter to quantitatively describe the phase separation extent. It was found that the phase separation degree of rrmm and rmmr is higher than that of mrrm and rmrm at the same temperature. The LCSTs of rrmm and rmmr are lower than those of mrrm and rmrm. The radial distribution function and hydrogen bond analysis revealed that the average values of hydrogen bonds between pentamers for rrmm and rmmr are greater than those of mrrm and rmrm, whereas the average values of hydrogen bonds between pentamers and water for rrmm and rmmr are less than those of mrrm and rmrm. It was demonstrated that the isotactic triad (mm) plays an important role in the thermosensitive behaviors of the PNIPAM pentamer. The increase of isotactic triad (mm) content in the PNIPAM chain promotes the formation of intermolecular hydrogen bonds between amide and amide and leads to a higher aggregation of the pentamer with the sequence of rrmm or rmmr. Finally, the effect of the isotactic triad was qualitatively explained with the mean-field theory.

Tuning pore structure of polymer-derived carbon materials for supercapacitor electrode materials using microscopic phase separation engineering

Specific surface area and pore structure have critical impact on the performance of carbon-based supercapacitors. However, for carbon materials, the association between pore architecture and electrochemical performance remains unclear. In this study, sub-nano porous carbon materials with precisely controllable pore size were fabricated by a simple direct carbonization method using interpenetrating polymer networks (IPN), Besides, the correlation between pore architecture and electrochemical performance was explored by controlling the relative content of the two polymer phases to enhance or weaken the degree of microscopic phase separation so as to modulate the pore structure. C-IPN1 exhibited the highest Specific Surface Area (SSA) at 827 m2 g−1, where micropores contributed 95.8 % for the total SSA. Within the three-electrode device, C-IPN1 provided an excellent Specific Capacitance of 238.5 F g−1 at the current density of 0.5 A g−1, which had high cycle stability (100 % capacity retention for 10,000 cycles) and achieved 79.5 % capacitance retention for 20-fold increase in current density (0.5 A g-1 to 10 A g−1). Furthermore, assembled symmetrical supercapacitors achieved an energy density of 7.31 Wh Kg−1 at the power density of 62.5 W Kg−1. This could provide a new avenue for the development of high-performance carbon electrode materials for double layer capacitors, given its simple synthesis process and excellent performance.

Correlating structure-mechanics relationship of multiblock copolymers: Insights from molecular dynamics simulation

Multiblock copolymers (MBCs) have garnered considerable interest in both industrial and fundamental polymer science. However, the phase structure and properties at a molecular level of MBCs remain largely unexplored. To address this, the effects of three structural factors (block number index α, interaction strength between hard segments εH−H, and hard segment stiffness kH) on the phase structure, dynamic properties and mechanical properties of MBCs have been investigated using coarse-grained molecular dynamics (CGMD) simulations. The degree of phase separation, ψ, has been quantified based on the number of neighboring beads designated to measure the phase separation structure. Results indicate that a lower α (longer block chain length), stronger εH−H, and weaker kH significantly reduce the contacts between soft and hard segments, leading to an increase in ψ. An examination of higher ψ (greater than 0.7) reveals two Tg s that converge as ψ decreases and eventually merge into one. Mechanical properties are improved with increasing α at low strains, whilst they change non-monotonically at high strains, likely due to differing contributions of soft and hard segments to the stress. Systems with stronger εH−H and kH exhibit superior mechanical properties due to their higher non-bonded energy increments and bond orientation. In general, the mode of the variation of phase separation structure, glass transition temperature and mechanical properties of MBCs at the molecular level, has been elucidated valuable insight for the design and synthesis of high-performance MBCs materials.

Shape memory polymer with programmable recovery onset.

Stimulus-responsive shape-shifting polymers1-3 have shown unique promise in emerging applications, including soft robotics4-7, medical devices8, aerospace structures9 and flexible electronics10. Their externally triggered shape-shifting behaviour offers on-demand controllability essential for many device applications. Ironically, accessing external triggers (for example, heating or light) under realistic scenarios has become the greatest bottleneck in demanding applications such as implantable medical devices8. Certain shape-shifting polymers rely on naturally present stimuli (for example,human body temperature for implantable devices)8 as triggers. Although they forgo the need for external stimulation, the ability to control recovery onset is also lost. Naturally triggered, yet actively controllable, shape-shifting behaviour is highly desirable but these two attributes are conflicting. Here we achieved this goal with a four-dimensional printable shape memory hydrogel that operates via phase separation, with its shape-shifting kinetics dominated by internal mass diffusion rather than by heat transport used for common shape memory polymers8-11. This hydrogel can undergo shape transformation at natural ambient temperature, critically with a recovery onset delay. This delay is programmable by altering the degree of phase separation during device programming, which offers a unique mechanism for shape-shifting control. Our naturally triggered shape memory polymer with a tunable recovery onset markedly lowers the barrier for device implementation.

Enhancement of rheological performance and compatibility of tire rubber-modified asphalt binder with the addition of graphene

Rubber segregation and workability are issues associated with tire rubber powder (TRP) modified asphalt binder, restricting its widespread application. Meanwhile, graphene nanoparticles have gained considerable interest in asphalt modification due to their outstanding properties. This work has explored the influence of graphene incorporation on the compatibility and rheological behavior of TRP-modified asphalt binder. Firstly, TRP-modified asphalt and two kinds of TRP/graphene composite-modified asphalt were prepared. Then, the rheological characteristics of the asphalts were investigated using the frequency sweep, temperature sweep, multiple stress creep and recovery (MSCR), linear amplitude sweep (LAS), and bending beam rheometer (BBR) tests. The compatibility and microstructure of the different modified asphalt binders were evaluated using the cigar tube test and scanning electron microscopy. Results showed that adding graphene to the TRP-modified asphalt resulted in a notable improvement in rutting performance, as evidenced by the increase in rutting parameter (G*/sinδ) and % recovery (R) and a decrease in non-recoverable creep compliance (Jnr). The graphene addition also enhanced the anti-aging performance of TRP-modified asphalt. The results obtained from the LAS test, including the damage-characteristic curves and the number of cycles to fatigue failure, suggested that the fatigue performance of the TRP/graphene composite-modified asphalt was higher compared to the TRP-modified asphalt. Similarly, the BBR test results with 12% TRP and 0.5% graphene demonstrated that the composite-modified asphalt was more resistant to low-temperature cracking. Finally, the incorporation of graphene can potentially reduce the degree of phase separation in TRP-modified asphalt binder and improve its compatibility.

Enhancing the Molecular Order and Vertical Component Distribution of the P3HT/O-IDTBR System during Layer-by-Layer Processing.

The molecular order and vertical component distribution are critical to enhance the charge transport in layer-by-layer (LbL) processed active layer. However, the excessive inter-diffusion between donor and acceptor layers during LbL processing irrepressibly reduces their ordered packing. Herein, a novel tactic to optimize the molecular order and vertical morphology of the active layer through suppressing the deep penetration of (5Z,5'Z)-5,5'-((7,7'-(4,4,9,9-tetraoctyl-4,9-dihydro-s-indaceno[1,2-b:5,6 -b']dithiophene-2,7-diyl)bis(benzo[c][1,2,5]thiadiazole-7,4-diyl))bis(methanylylidene)) bis(3-ethyl-2-thioxothiazolidin-4-one) (O-IDTBR) to poly(3-hexylthiophene) (P3HT) film during LbL processing is proposed. This is enabled by inducing the formation of P3HT nanofibers through ultraviolet (UV) irradiation and solution aging. During the LbL processing, these nanofibers with high crystallinity reduce the damage of O-IDTBR solution to P3HT film and restrict the penetration of O-IDTBR into P3HT matrix. As a result, the P3HT nanofibers are preserved and the degree of vertical phase separation is enlarged in the LbL-processed film. Meanwhile, the molecular order of both components is enhanced. The resulting morphology that featured as intertwined P3HT nanofibers/O-IDTBR network efficiently promotes charge transport and extraction, boosting the power conversion efficiency (PCE) of the devices from 6.70±0.12% to 7.71±0.10%.

Stable and impalement-resistant superamphiphobic coatings enabled by phase-separated adhesive for anti-adhesion of viscous liquids with low surface tension

Superamphiphobic coatings have great potential in various fields but surfer from weak mechanical stability, low impalement resistance and poor repellency to viscous liquids with low surface tension. Here, we report stable and impalement-resistant superamphiphobic coatings enabled by phase-separated adhesive for anti-adhesion of viscous liquids with low surface tension. By fluorination of silica (F-silica) nanoparticles and solvent induced phase separation of an adhesive, a homogeneous suspension was obtained, which could be readily used for preparing superamphiphobic coatings via spray-coating. The effects of phase separation degree and adhesive/F-silica mass ratio on superamphiphobicity, impalement resistance and mechanical stability of the coatings were studied. The coatings have a hierachical micro-/nanostructure and numerous perfluorodecyl groups on the surface. Thus, the coatings show excellent static and dynamic superamphiphobicity, e.g., high contact angles, low sliding angles, high maximum release height, short solid-liquid contact time and large bouncing height for various liquids with high viscosity and low surface tension. The coatings also show excellent mechanical stability, good chemical and temperature stability. Furthermore, the coatings are applicable onto diverse substrates and could be easily scaled-up.

Sustainable and greener coatings produced from accelerator‐ and sulfur‐free polyurethane dispersion/carboxylated nitrile butadiene latex blends

AbstractThis study is aimed at producing polyurethane dispersion (PUD)/carboxylated nitrile butadiene rubber (XNBR) blends without using accelerators and sulfur. The PUD/XNBR (at blending ratios of 90:10, 80:20, 70:30, and 60:40) was prepared using coagulation and latex dipping technology. The result demonstrated that increasing XNBR in the PUD/XNBR blends increased the zeta potential of the blends up to −71.8 mV. Fourier transform infrared (FTIR) studies show hydrogen interaction bonding exists between XNBR and PUD, which significantly impacts the degree of phase mixing, degree of phase separation and relative change of hard segment separation of the PUD. The surface energy of the PUD blend is reduced from 34.68 ± 0.23 to 22.28 ± 0.63 mJ−2 with increasing XNBR loading. The presence of XNBR had increased the polar component of the surface energy, but a further increase of the XNBR amount to more than 20% had reduced the tensile strength. Overall, loading 20% of XNBR (PUD80) showed the best performance by having an improvement in tensile strength compared to pristine PUD.

High-damping polyurethane-based composites modified with amino-functionalized graphene

A series of damping composites containing polyurethane/poly (butyl methacrylate) (PU/PBMA) as the polymer matrix and graphene nanoplates (GNP) or amino-functionalized graphene nanoplates (NGNP) as a modifier was successfully synthesized through in situ polymerization. The chemical structure, microphase configuration, damping properties, and thermal stability of the GNP–PU/PBMA and NGNP–PU/PBMA composites were evaluated. Fourier-transform infrared and X-ray photoelectron spectroscopic studies revealed that the amino (–NH2) groups on the NGNP surface presumably reacted with the isocyanate (R–N = C = O) groups of the polymer matrix. This led to robust bonding between the NGNP and the hard segments in PU, resulting in an NGNP/polymer-matrix compatibility superior to that of GNP–PU/PBMA. Structural investigations based on scanning electron microscopy and atomic force microscopy revealed dispersion-state-related differences between the GNP and NGNP in the PU/PBMA matrix; the amino-functionalized GNP were more uniformly dispersed in the polymer matrix than their unmodified counterparts, and microphase separation between the hard and soft segments intensified in NGNP–PU/PBMA, resulting in a greater degree of phase separation, as confirmed by small-angle X-ray scattering analysis. Dynamic mechanical analysis (DMA) revealed that the maximum damping peak (tan δmax) of the composite with 0.7 wt.% NGNP was 22.7% higher than that of pristine PU/PBMA. Additionally, a large independent damping peak appeared in the DMA curve of 0.7 wt.% NGNP–PU/PBMA in the high-temperature range, indicating broadening of the damping temperature range. Moreover, the NGNP incorporation effectively improved the thermal stability of the composite. Overall, this study demonstrates the viability of realizing PU-based materials with excellent thermodynamic and damping properties by incorporating amino-bearing NGNP.

Study on high moisture extruded pea protein isolate based on acid-induced process: Physicochemical properties, conformational changes and fibrous structure mechanism

The present study aims to gain a better understanding of the physicochemical properties and quality attribute changes, and fibrous structure formation mechanisms of pea protein analogs with different glucan-δ-lactone (GDL) additions under high moisture extrusion. The results showed that the pH value of the extrudates gradually approached the isoelectric point and the zeta potential increased with the increase in GDL, which reduced the water holding capacity, nitrogen solubility index and browning index values, while increasing the hardness, chewiness and fibrous degree of the extrudates. The comparison revealed the maximum zeta potential value and total SH, and minimum free SH of the raw material, suggesting the unfolding and cross-linking of proteins under the triple action of the extruder. The relative content of β-sheet as the predominant component of protein extrudate decreased, while α-helix increased, and λmax was bathochromiclly shifted through FTIR and fluorescence spectroscopy. However, negative trends were observed when the GDL concentration reached 1%, due to the excessive concentration of the GDL accelerating the aggregation and sedimentation of proteins, and intensified the phase separation degree in the cooling die during the extrusion process, thus promoting the change in the velocity gradient. In addition, the thermal stability of the extrudate first increased and then decreased as the GDL concentration increased, and showed a three-step thermal degradation stage. The pores and highly irregular fibrous filaments transformed into a highly compact and coarse matrix with an excessive GDL concentration, as observed by SEM. These findings validate the potential of GDL to improve the textural attributes and structure formation of meat analogs, and provide a reference for the development of acid-induced proteins under high moisture extrusion.

Phase-Separated Dielectric Gels Based on Christiansen Effect.

Phase separation is a trivial phenomenon but a mature strategy in materials science. The flexible materials are provided toughness and strength by phase separation, yet there are few applications in optics and electronics industry. A novel phase-separated dielectric gel (PSDG) with a strong Christiansen effect is prepared via radical polymerization using hydroxyethyl methacrylate as a monomer, 4-cyano-4'-pentylbiphenyl and tributyl citrate as mixed solvents, and polyethylene glycol as a softener. The solvent ratios and ambient conditions can efficiently change the color of PSDG which makes it strongly selective for the wavelength of transmitted light. Besides, it has a high dielectric constant (10 at 1kHz), sensitively responding to the electric field. The phase separation degree of PSDG varies with applied electric field, which will induce its transmittance alteration accordingly. The current field sensitive PSDG provides a novel idea for "smart windows". Additionally, varying the size and shape of the electrodes can precisely control the phase separation in PSDG and also enables the function of free writing on flexible materials. Therefore, the designed PSDG has great application potential for flexible touch and interesting interactions.

Modulation of Alkyl Chain Length on the Thiazole Side Group Enables Over 17% Efficiency in All‐Small‐Molecule Organic Solar Cells

AbstractMolecular innovation is highly desirable to achieve efficient all‐small‐molecule organic solar cells (SM‐OSCs). Herein, three small‐molecule donors (SMDs) with alkylated thiazole side groups (namely BO‐1, HD‐1, and OD‐1), which differ only in the alkyl side chain are reported. Although these SMDs possess similar absorption profiles and molecular energy levels, their crystallinity and miscibility with BTP‐eC9 slightly decrease along with the elongation of the alkyl side chain. After blending with BTP‐eC9, different miscibility leads to different degrees of phase separation. Among these SM‐OSCs, the HD‐1‐based device shows a decent bulk‐heterojunction (BHJ) morphology with proper phase separation and more dynamic carrier behavior. Thus, compared to the BO‐1 and OD‐1‐based devices, the HD‐1‐based device achieves a higher short‐circuit current of 26.04 mA cm−2 and a fill factor of 78.46%, leading to an outstanding PCE of 17.19%, which is one of the highest values among SM‐OSCs. This work provides a rational design strategy of SMDs for highly efficient SM‐OSCs.

Synthesis and characterization of poly(tetramethylene oxide)-based segmented ionenes block copolymer with aliphatic or DABCO hard segments

In this study, the effects of the contents of the soft and hard segments as well as the type of hard segments (linear aliphatic and DABCO) on the properties of PTMO-based segmented ionenes were investigated. DSC revealed that soft segment weight fractions up to 75 wt% induced heterogeneous crystallization while the melting temperature decreased due to the lower degree of crystallization. DMA showed the formation of a higher degree of ionic aggregates in both linear aliphatic and DABCO-based PTMO ionenes with 25 wt% of soft segment resulting from strong Coulombic interactions between hard segments. DABCO-based ionenes showed a higher degree of phase separation compared to linear aliphatic analogs and displayed a long-range ordered lamellar structure. In contrast, linear aliphatic ionenes showed the formation of random ionic domains, which was confirmed by SAXS and AFM. TGA showed that the PTMO-based ionenes were thermally stable up to 250 °C and suggested that the DABCO hard segment has a weaker protective effect against the degradation of the PTMO soft segment at elevated temperatures compared to the linear aliphatic hard segment. Uniaxial tensile tests exhibited stress-induced crystallization of PTMO-based ionenes, high elongation at break with linear aliphatic hard segment compared to the DABCO hard segment, and the opposite trend of Young's modulus and ultimate tensile strength by changing the type of the hard segment.

Entropically-Driven Co-assembly of l-Histidine and l-Phenylalanine to Form Supramolecular Materials.

Molecular self- and co-assembly allow the formation of diverse and well-defined supramolecular structures with notable physical properties. Among the associating molecules, amino acids are especially attractive due to their inherent biocompatibility and simplicity. The biologically active enantiomer of l-histidine (l-His) plays structural and functional roles in proteins but does not self-assemble to form discrete nanostructures. In order to expand the structural space to include l-His-containing materials, we explored the co-assembly of l-His with all aromatic amino acids, including phenylalanine (Phe), tyrosine (Tyr), and tryptophan (Trp), all in both enantiomeric forms. In contrast to pristine l-His, the combination of this building block with all aromatic amino acids resulted in distinct morphologies including fibers, rods, and flake-like structures. Electrospray ionization mass spectrometry (ESI-MS) indicated the formation of supramolecular co-assemblies in all six combinations, but time-of-flight secondary-ion mass spectrometry (ToF-SIMS) indicated the best seamless co-assembly occurs between l-His and l-Phe while in the other cases, different degrees of phase separation could be observed. Indeed, isothermal titration calorimetry (ITC) suggested the highest affinity between l-His and l-Phe where the formation of co-assembled structures was driven by entropy. In accordance, among all the combinations, the co-assembly of l-His and l-Phe produced single crystals. The structure revealed the formation of a 3D network with nanocavities stabilized by hydrogen bonding between -N (l-His) and -NH (l-Phe). Taken together, using the co-assembly approach we expanded the field of amino acid nanomaterials and showed the ability to obtain discrete supramolecular nanostructures containing l-His based on its specific interactions with l-Phe.

Experimental study of ensemble phase splitting features of water-oil slug/droplet flow at a branching micro-T-junction

This paper reports the ensemble phase splitting features of water-oil slug/droplet flow at a micro-T-junction with three equal branches. The hydraulic diameter of the channels is around 850 µm. The slug flow shows almost no phase separation (even splitting) at various splitting ratios of continuous flow, which agrees with the prediction of a traditional mechanism. Despite that the morphology of the studied droplet flow apparently looks like slug flow, the phase splitting features of them are distinctively different. At certain conditions, the separation degree of water and oil of droplet flow reaches as high as 45 %. The “abnormal” uneven phase splitting features are resulted from the transition of splitting mode of dispersed phase from pressure dominant process to shear dominant process. The high phase separation degree can be achieved by increasing Capillary (Ca) number of the continuous flow to a critical value larger than 0.02 and increasing the splitting ratios of continuous flow slightly larger than 0.5. The mechanism is discussed to understand these “abnormal” splitting features of droplet chains at high Ca number.

Synthesis of Novel Shape Memory Thermoplastic Polyurethanes (SMTPUs) from Bio-Based Materials for Application in 3D/4D Printing Filaments.

Bio-based thermoplastic polyurethanes have attracted increasing attention as advanced shape memory materials. Using the prepolymer method, novel fast-responding shape memory thermoplastic polyurethanes (SMTPUs) were prepared from 100% bio-based polyester polyol, poly-propylene succinate derived from corn oil, diphenyl methane diisocyanate, and bio-based 1,3-propanediol as a chain extender. The morphologies of the SMTPUs were investigated by Fourier transform infrared spectroscopy, atomic force microscopy, and X-ray diffraction, which revealed the interdomain spacing between the hard and soft phases, the degree of phase separation, and the intermixing level between the hard and soft phases. The thermal and mechanical properties of the SMTPUs were also investigated, wherein a high hard segment content imparted unique properties that rendered the SMTPUs suitable for shape memory applications at varying temperatures. More specifically, the SMTPUs exhibited a high level of elastic elongation and good mechanical strength. Following compositional optimization, a tensile strength of 24-27 MPa was achieved, in addition to an elongation at break of 358-552% and a hardness of 84-92 Shore A. Moreover, the bio-based SMTPU exhibited a shape recovery of 100%, thereby indicating its potential for use as an advanced temperature-dependent shape memory material with an excellent shape recoverability.

Highly Efficient Ternary Near-Infrared Organic Photodetectors for Biometric Monitoring.

Near-infrared (NIR) small-molecule acceptors that absorb at wavelengths of up to 1000 nm are attractive for applications in organic photodetectors (OPDs) and biometrics. In this study, we incorporated IEICO-4F as the third component for PffBT4T-2OD:PC71BM-based OPDs to provide an efficient NIR response while greatly suppressing the leakage current at reverse bias. By varying the blend ratio and thickness (250-600 nm), we obtained an NIR OPD displaying an ultralow dark-current density (JD = 2.62 nA cm-2), ultrahigh detectivity [D* = 7.2 × 1012 Jones (850 nm)], high sensitivity, and photoresponsivity covering the region from the ultraviolet to the NIR. We used tapping-mode atomic force microscopy, optical microscopy, grazing-incidence wide-angle X-ray scattering, and contact angle measurements to investigate the effect of IEICO-4F on the performance of the ternary OPDs. The low compatibility of PffBT4T-2OD and IEICO-4F, originating from weak intermolecular interactions, allowed us to manipulate the degree of phase separation between the donor and acceptor in the ternary blends, leading to an optimized blend morphology featuring efficient charge separation, transport, and collection. To demonstrate its applicability, we integrated our OPD with two light-emitting diodes and used the system for precisely calculated transmissive pulse oximetry.

Synthesis and characterization of hydroxyl-terminated polybutadiene modified low temperature adaptive self-matting waterborne polyurethane.

Hydroxyl-terminated polybutadiene (HTPB) is a flexible telechelic compound with a main chain containing a slightly cross-linked activated carbon-carbon double bond and a hydroxyl group at the end. Therefore, in this paper, HTPB was used as a terminal diol prepolymer, and sulfonate AAS and carboxylic acid DMPA were used as hydrophilic chain extenders to prepare low-temperature adaptive self-matting waterborne polyurethane (WPU). Due to the fact that the non-polar butene chain in the HTPB prepolymer cannot form a hydrogen bond with the urethane group, and the solubility parameter difference between the hard segment formed by the urethane group is large, the gap of T g between the soft and hard segments of the WPU increases by nearly 10 °C, with more obvious microphase separation. At the same time, by adjusting the HTPB content, WPU emulsions with different particle sizes can be obtained, thereby obtaining WPU emulsions with good extinction properties and mechanical properties. The results show that HTPB-based WPU with a certain degree of microphase separation and roughness obtained by introducing a large number of non-polar carbon chains has good extinction ability, and the 60° glossiness can be as low as 0.4 GU. Meanwhile, the introduction of HTPB can improve the mechanical properties and low temperature flexibility of WPU. The T g,s (the glass transition temperature of soft segment) of WPU modified by the HTPB block decreased by 5.82 °C, and the ΔT g increased by 21.04 °C, indicating that the degree of microphase separation increased. At -50 °C, the elongation at break and tensile strength of WPU modified by HTPB can still maintain 785.2% and 76.7 MPa, which are 1.82 times and 2.91 times those of WPU with only PTMG as soft segment, respectively. The self-matting WPU coating prepared in this paper can meet the requirements of severe cold weather and has potential application prospects in the field of finishing.

THE STUDY OF INTERMOLECULAR INTERACTIONS IN THE POSS-CONTAINING NANOCOMPOSITES BASED ON POLYURETHANE AND POLYURETHANE/POLY(HYDROXYPROPYL METHACRYLATE) MATRICES

The nanocomposites based on polyurethane matrix and multicomponent polymer matrices consisting of polyurethane and poly(hydroxypropyl methacrylate) with different contents of the last, and 1,2-propanediolisobutyl polyhedral oligomeric silsesquioxane (1,2-propanediolisobutyl-POSS), which was used as a functionalized nanofiller, were synthesized. The influence of the content of 1,2-propanediolisobutyl-POSS on intermolecular interactions and structural features of the nanocomposites was investigated by the method of IR-spectroscopy with Fourier transformation and attenuated total reflection (FTIR-ATR). The study of thermal curing of the model system, which consists of the adduct of trimethylolpropane with toluene diisocyanate and 1,2-propanediolisobutyl-POSS, made it possible to conclude that 1,2-propanediolisobutyl-POSS participates in the reaction of urethane formation using of one of the terminal hydroxyl groups, and it is incorporated into the polymer chain between cross-linking of polyurethane networks. The investigation of multicomponent polymer matrices by FTIR-ATR spectroscopy was done and was shown that photopolymerization of second polymer poly(hydroxypropyl methacrylate) in the matrix of polyurethane was completed by the opening of a double bond and the formation of a linear polymer in the composition of semi-IPN. Studies of nanocomposites based on multicomponent polymer matrices consisting of polyurethane and poly(hydroxypropyl methacrylate) with 15 and 30 % of the last by FTIR-ATR spectroscopy demonstrated the presence of POSS in the nanocomposites and the influence of POSS content on the structure of the studied systems and on the degree of phase separation. The POSS is "embedded" into the polymer chain between cross-linking of the polyurethane networks, with the additional formation of a complex system of intermolecular hydrogen bonds between the carboxyl and amine components of urethane groups in the nanocomposites.