Intrinsic Viscosity Research Articles

Discriminating the viscoelastic properties of cellulose textile fibers for recycling

The viscoelastic properties of cellulose fibers play an important role in chemical recycling of textiles. Here we discriminated the intrinsic viscosity of cotton roll towels and bed linens using near-infrared imaging spectroscopy and supervised pattern recognition. The classification results showed training and test set accuracies of 84–97% and indicated that the relevant spectral features were related to water, cellulose, and cellulose crystallinity. We hypothesized that the decreasing intrinsic viscosity of cotton was associated with changes in cellulose crystallinity and water adsorption, which was supported by additional X-ray and sorption measurements. These results are important as they indicate the potential to non-invasively estimate the degree of polymerization and the suitability of different cotton materials for chemical recycling. We propose that changes in the degree of polymerization and cellulose crystallinity could be used as an indicator of the chemical quality of cellulose fibers, which would have wider impacts for textile recycling.

Co-assembly of Ag nanowires and nanocubes mediated by adhesive tape in hydrophilic and hydrophobic pattern for SERS-based determination of gefitinib and ritonavir in serum

Controlled aggregation of noble metal nanoparticles is incredibly crucial for obtaining reliable surface-enhanced Raman scattering (SERS) properties. Here, a rational agglomeration of large Ag nanowires (NWs) and small Ag nanocubes (NCs) was readily facilitated by simply utilizing the intrinsic viscosity of adhesive tape, leading to the generation of abundant electromagnetic “hotspots” around the numerous crossed nanotips and ultra-small nanogaps. After the molecular enrichment efficiency was further promoted by exploiting a hydrophilic-hydrophobic strategy, an ultra-low limit of detection as 8.8 × 10−11 M was demonstrated for rhodamine 6 G. Benefiting from the high sensitivity of the SERS chip, its application in the determination of clinical sample containing mixed gefitinib and ritonavir was finally proved, facilitating impressive specificity and accuracy. Considering the simplicity and reliability, our strategy has great potentials to be applied in clinical blood drug identification and concentration monitoring.

Study on Properties and Degradation Behavior of Poly (Adipic Acid/Butylene Terephthalate-Co-Glycolic Acid) Copolyester Synthesized by Quaternary Copolymerization

At present, the development and usage of degradable plastics instead of traditional plastics is an effective way to solve the pollution of marine microplastics. Poly (butylene adipate-co-terephthalate) (PBAT) is known as one of the most promising biodegradable materials. Nevertheless, the degradation rate of PBAT in water environment is slow. In this work, we successfully prepared four kinds of high molecular weight polyester copolyesters (PBATGA) via quaternary copolymerization. The results showed that the intrinsic viscosity of PBATGA copolymers ranged from 0.74 to 1.01 dL/g with a glycolic acid content of 0-40%. PBATGA copolymers had excellent flexibility and thermal stability. The tensile strength was 5~40 MPa, the elongation at break was greater than 460%, especially the elongation at break of PBATGA10 at 1235%, and the thermal decomposition temperature of PBATGA copolyesters was higher than 375 °C. It was found that PBATGA copolyester had a faster hydrolysis rate than PBAT, and the weight loss of PBATGA copolymers showed a tendency of pH = 12 > Lipase ≈ pH = 7 > pH = 2. The quaternary polymerization of PBAT will have the advantage of achieving industrialization, unlike the previous polymerization process. In addition, the polymerization of PBATGA copolyesters not only utilizes the by-products of the coal chemical industry, but also it can be promising in the production of biodegradable packaging to reduce marine plastic pollution.

Rigid rod particle like viscoelastic responses of poly(vinylidene fluoride) in N-methylpyrrolidone solution

A systematic study was performed on the dynamic viscoelastic properties of N-methylpyrrolidone (NMP) solutions of poly(vinylidene fluoride) (PVDF) samples with a wide range of weight average molar masses (Mw) from 140 to 3300 kg mol−1 over a temperature range of −24 to 35 °C in the dilute to semidilute concentration (c) regime in this study. In previous studies under extremely dilute conditions, it was confirmed that PVDF molecules behave as isolated highly elongated rigid rods, and the average particle length (⟨L⟩) and diameter (⟨d⟩) for different PVDF samples were precisely determined. The fundamental viscoelastic parameters used to analyze the dynamics of PVDF molecules dissolved in NMP were precisely determined, including the zero-shear shear viscosity (η0), the steady state compliance (Je), the average relaxation time (τw), and the activation energy (E*v) of τw in this study. E*v increased stepwise above c values corresponding to the reciprocal of the intrinsic viscosity ([η]−1) for different solutions, independent of Mw, showing that contact or the formation of entanglements between PVDF molecules causes the increase in E*v. Je−1 was found to be proportional to the number density of PVDF molecules (ν = cNAMw−1, where NA denotes the Avogadro constant) over the entire investigated v range, irrespective of Mw and the presence of entanglements between PVDF molecules. The reduced specific viscosities, ηspNA⟨L⟩3(Mw[η])−1, were reasonably described as a universal function in the parameter ν⟨L⟩3 over the entire investigated range, and ηspNA⟨L⟩3(Mw[η])−1 ∝ (ν⟨L⟩3)3 was found over the region 102 < ν⟨L⟩3 < 103, irrespective of Mw.

Optimizing the Flocculation Effect of Cationic Polyacrylamide Prepared with UV-Initiated Polymerization by Response Surface Methodology

Cationic polyacrylamide (CPAM) is a commonly used flocculant for water treatment. Factors that affect the flocculation effect and can be controlled manually include the type and dosage of CPAM, wastewater pH, stirring time and settling time, and their reasonable setting is critical to the flocculation effect of CPAM. In this paper, the optimal flocculation conditions of a novel CPAM were studied. First, single-factor tests were conducted to preliminarily explore the optimal range of factors that influence CPAM flocculation, and then response surface methodology (RSM) tests were performed to accurately determine the optimums of the influencing factors. The results showed that the flocculation effect was better when the intrinsic viscosity was larger or the cationic degree of CPAM was higher. The CPAM dosage, wastewater pH and stirring time significantly impacted the flocculation effect, and inflection points were observed. A model that could guide CPAM-8.14-40.2 flocculation was obtained by RSM tests. The model optimization showed that the optimal flocculation conditions of CPAM-8.14-40.2 for treating wastewater prepared with kaolin were as follows: the CPAM dosage, wastewater pH and stirring time were 5.83 mg·L−1, 7.28, and 5.95 min, respectively, and the turbidity of the treated wastewater was reduced to 6.24 NTU.

Brownian motion of poly(divinylbenzene) nanoparticles in water

Understanding the motion of nanoparticles in liquid is of practical importance for drug delivery and fluid flow in nanofluidic systems. In this work, we use a nanoparticle tracking analyzer to investigate the Brownian motion of polydivinylbenzene (PDVB) nanoparticles in water and a video camera to record the aggregation of PDVB aggregates on the water surface. Using water as the liquid medium precludes the possible complex interaction between the liquid medium and the PDVB nanoparticles, which can possibly alter the random characteristics of the motion of the PDVB nanoparticles. The diffusivity of the PDVB nanoparticles determined from the mean square displacements of the PDVB nanoparticles has the same activation energy as that for the intrinsic viscosity of the corresponding aqueous suspension of the PDVB nanoparticles. The correlation between the diffusivity for the motion of the PDVB nanoparticles in water and the intrinsic viscosity of the corresponding aqueous suspension follows the Stokes–Einstein relation. The capillary effect and the interaction between PDVB aggregates and the liquid media enable the aggregation of the PDVB aggregates on the water surface, which follows the first-order reaction with activation energy larger than that for the random motion of the PDVB nanoparticles in water.

Study of Properties of Polyethylene Glycol and Its Glass Fibers Composites under UV-Rad for Oils Filtration Applications

This study determines the effects of UV radiation and heat treatment on many flow and mechanical parameters of PEG 4000, including flow time and viscosity (specific, reduced, relative, and intrinsic). Solubility time and shore D hardness are among the mechanical characteristics. By adjusting the concentrations of solutions in the range (0.01–0.03) g/ml of heating and non-heating PEG powders, and examining the polymer's solubility at the same time, the flow characteristics of the polymer are explored. Random glass fiber reinforcement in the range of 0.1–0.4 wt has also been studied to indicate the effect on shore hardness. After exposing the produced plates to ultraviolet light, the efficacy of the plates in purifying the oil from contaminants was investigated. The results show that increasing the concentration increases all types of viscosity and flow time, with the exception of intrinsic viscosity, which decreases as concentrations increase. Other parameters decrease after the first UV ray and heat treatment, but increase as the time of UV ray treatment increases. Furthermore, increasing the weight ratio of glass fibers from 0.1 to 0.4 wt lowered shore hardness, whereas increasing the weight ratio at the same previous range increased it after UV rad. While solubility data refers to increasing polymer weight and radiation help increase solubility time. The filtration efficacy of the small particles of the produced filters increased after the overlapping plates were exposed to UV radiation, owing to the smaller pore diameters.

Challenging the Kauzmann paradox using an ultra-stable perfluoropolymer glass with a fictive temperature below the dynamic VFT temperature

Ultra-stable fluoropolymer glasses were created using vacuum pyrolysis deposition that show large fictive temperature Tf reductions relative to the glass transition temperature Tg of the rejuvenated material. Tf was also found to be 11.4 K below the dynamic VFT temperature TVFT. Glass films with various thickness (200–1150 nm) were deposited onto different temperature substrates. Glassy films were characterized using rapid-chip calorimetry, Fourier-transform infrared spectroscopy and intrinsic viscosity measurements. Large enthalpy overshoots were observed upon heating and a Tf reduction of 62.6 K relative to the Tg of 348 K was observed. This reduction exceeds values reported for a 20-million-year-old amber and another amorphous fluoropolymer and is below the putative Kauzmann temperature TK for the material as related to TVFT. These results challenge the importance of the Kauzmann paradox in glass-formation and illustrates a powerful method for the exploration of material dynamics deep in the glassy state (Tf < T < Tg).

Fine structural features and antioxidant capacity of ferulated arabinoxylans extracted from nixtamalized maize bran.

The nixtamalization process improves the nutritional and technological properties of maize. This process generates nixtamalized maize bran as a by-product, which is a source of arabinoxylans (AX). AX are polysaccharides constituted of a xylose backbone with mono- or di-arabinose substitutions, which can be ester-linked to ferulic acid (FA). The present study investigated the fine structural features and antioxidant capacity (AC) of nixtamalized maize bran arabinoxylans (MBAX) to comprehend the structure-radical scavenging capacity relationship in this polysaccharide deeply. MBAX presented a molecular weight, intrinsic viscosity, and hydrodynamic radius of 674 kDa, 1.8 dL g-1 , and 24.6 nm, respectively. The arabinose-to-xylose ratio (A/X) and FA content were 0.74 and 0.25 g kg-1 polysaccharide, respectively. MBAX contained dimers (di-FA) and trimer (tri-FA) of FA (0.14 and 0.07 g kg-1 polysaccharide, respectively). The main di-FA isomer was the 8-5' structure (80%). Fourier transform infrared spectroscopy confirmed MBAX molecular identity, and the second derivate of the spectral data revealed a band at 958 cm-1 related to the presence of arabinose disubstitution. 1 H-Nuclear magnetic resonance spectroscopy showed mono- and di-arabinose substitution in the xylan backbone with more monosubstituted residues. MBAX registered an AC of 25 and 20 μmol Trolox equivalents g-1 polysaccharide despite a low FA content, using ABTS (2,2'-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid) and DPPH (1,1-diphenyl-2-picrylhydrazyl) methods, respectively. AC in MBAX could be related to the high A/X ratio (mainly monosubstitution) and the high 8-5' di-FA proportion in this polysaccharide. © 2023 Society of Chemical Industry.

TECHNOLOGY FOR OBTAINING SUPERCONCENTRATES (MASTERBATCH) BASED ON ALCOHOLYSIS PRODUCTS OF SECONDARY POLYETHYLENE TEREPHTHALATE

Regularities of alcoholysis of secondary polyethylene terephthalate (RPET) by diethylene glycol (DEG) have been studied. It is shown that with an increase in the amount of diethylene glycol taken for alcoholysis from 0.1 mol to 0.4 mol per 1 mol of the elementary unit of HPET, a decrease in molecular weight from 1480 to 707 and the associated melting point from 215 to 145 °C are observed, and also intrinsic viscosity from 0.075 to 0.05 dl/g. The physicochemical properties of the products of alcoholysis of SPET (PAPET) have been determined. It has been revealed that PAPET is slightly colored and this is an undesirable factor affecting the individuality of the color of masterbatches based on them. Washing out with PAPET leads to some increase in the molecular weight values and related other indicators of the final oligomers. The structure of PAPET has been studied by infrared spectroscopy and differential scanning calorimetry. It has been revealed that PAPET synthesized at a molar ratio of SPET : DEG of 1:0.4, in which the dropping point according to Ubellode is 155 °C, is most suitable for obtaining superconcentrates. On the basis of PAPET obtained under these conditions, formulations of black and white masterbatches for polyethylene terephthalate fibers have been developed. To ensure uniform dispersion of white (TiO2) and black (K-354 carbon black) pigments, polyethylene wax was added to the superconcentrates. Masterbatches have been obtained by dry method in a twin screw compounder equipped with a double strand head and a granulator. The technological properties of the developed black and white superconcentrates have been determined, which turned out to be very close to those of the superconcentrates used in production. Conducted production tests of these masterbatches have showed that they are not inferior in terms of performance to similar industrial masterbatches used for dyeing threads.

Hofmeister series: An insight into its application on gelatin and alginate-based dual-drug biomaterial design

Alginate and gelatin are bio-polymers widely used in drug delivery. A range of salts can be used to achieve the required flexibility in biomaterial design. Hofmeister series gives an idea about the behaviour of salts with proteins. However, its application for the design of biomaterials and their specific effect on high-viscosity polymers and polymer mixtures has not quite been explored. Firstly, this work proposes a strategic interaction-based approach for designing a dual-drug ocular biomaterial. Secondly, the impact of different salt anions on gelatin and alginate mixture for the developed protocols is studied by a proposed method of determining shear-dependent general intrinsic viscosity. Thirdly, shear-dependent intrinsic viscosity is used to determine the interaction amongst the polymers in their mixture, which is then correlated to the release profiles and hydrodynamic radii of polymer mixtures. It is observed that Hofmeister anions behave reversely for high-viscosity negatively charged polymers and depends on the charge densities of the anions. For the polyelectrolyte/polyampholyte complex/mixture, the interactions depend on the addition sequence. It is inferred that the kosmotropes are preferred for protocols where salt is added between gelatin and alginate and chaotropes for protocols where salt is added to the gelatin and alginate complex/mixture in terms of release profiles.

Polymers and rheology: A tale of give and take

Polymers and rheology were both born in the twenties of the last century, fruit of the disruptive and creative scientific atmosphere of this decade. The development of polymer science and technology in the last almost 100 years has been colossal, whereas rheology has been able to create its own route as a branch of Physics. In this review paper we describe the interactions between both scientific areas, demonstrating that many of the crucial aspects for the progress of one of them owes to contribution of the other and viceversa. This interrelationship is shown through a historical survey of the principal milestones, starting from the correlation of the molecular weight with the intrinsic viscosity. A pondered analysis of the contributions of rheology to polymer science and technology, lead us to assert that the role of the former is rather founded on 50 years old discoveries.

Fe(II)-Based Metallo-Supramolecular Polymer Film for Electrochemical Detection of Nitrite: Studies of Kinetics and Reaction Mechanisms

Here, a monometallic supramolecular polymer (SMP) was synthesized for the fabrication of an electrochemical nitrite sensor, and a mechanism for nitrite detection was proposed based on the experimental findings. The SMP (polyFe) was synthesized using a symmetrical ligand containing terpyridine moieties [4′,4′′′′-(1,4- Phenylene) bis(2,2′:6′,2′′-terpyridine)] and ferrous acetate. Various analytical methods, such as ultraviolet/visible (UV/Vis) titration, field-emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), and energy dispersive X-ray spectroscopy (EDS), were used to characterize polyFe. The molecular weight of polyFe was calculated from the intrinsic viscosity measurement using the Mark-Houwink-Sakurada equation. The electrochemical behavior of the fabricated sensor was investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The variation in scan rate from CV was used to investigate the kinetics of nitrite oxidation. A possible reaction mechanism was proposed based on the kinetic studies. The proposed sensor showed a good linear range of 2.49 μM to 1.23 mM and a limit of detection of 0.17 μM. Stability, interference, and reproducibility of the proposed sensor were also investigated. The CV technique was used to demonstrate the applicability of the nitrite sensor for real sample analysis. A satisfactory recovery with a low relative standard deviation was achieved.

RADICAL COPOLYMERIZATION AND DETERMINATION OF THERMAL STABILITY OF SOME NEW SUBSTITUTED PHENYL MALEIMIDE POLYMERS

This article investigated a study and application of Kuhan-mark Howink Sakwada equation on some maleimides polymerand find out a relation in between intrinsic viscosity and molecular weight. Proposed work taken some maleimidesubstituted compounds and their study. In the research we selected some new maleimides monomer like as N-(ONitrophenyl)maleimide, N-(M-Nitro phenyl) maleimide and N-(P-Nitro phenyl) maleimide. Monomers werecopolymerized with methyl methacrylate. Synthesized homo and copolymers were characterized by FT-IR and 1H-NMRspectroscopy. Prepared monomers were polymerized at 12, 36, 48 and 72 hours on magnetic stirrer and AIBN and BPOused as a free radical initiator. THF and DMF were used as a solvent. Percentage yield were determined with timevariations. Number average and weight average molecular weight was determined by the gel permissionchromatography. Intrinsic viscosity was determined by the Hubelhod viscometer and thermal stability was determined bythe TGA techniques and starting degradation temperature and final degradation temperature was recorded.Polymerization reaction proceed via free radical is determined by the PDI index. Percentage composition of N and C iscalculated in monomer and polymer. This article focused that what actual shape of the homopolymer and copolymershowing in solvent and determined by Kuhan-mark Howink Sakwada equation.

Dry‐jet wet spinnability of poly(1,4‐phenylene‐1,3,4‐oxadiazole) fiber: The influence of polymer intrinsic viscosity and spinning dope temperature

AbstractThe spinnability of poly (p‐phenyl‐oxadiazole) (POD) spinning dope was regulated by tuning intrinsic viscosity and temperature to make it feasible for dry‐jet wet spinning. An increase in intrinsic viscosity ([η]) and a decrease in temperature will give rise to a more significant entanglement density of the POD solution and increase viscosity. Results show that POD spinning dopes' stable extrusion can be formed at the conditions when the spinning dope's viscoelastic transition frequency (VETF) is around 10 Hz. The solution was selected to prepare POD fiber when [η] = 2.23 at 40 °C, and the tensile strength of the POD fiber was enhanced significantly (from 1.3 to 3.19 cN/dtex). The best mechanical properties were achieved when the draw ratio at the spinneret was 1.6. Our work provides an alternative for the rapid preparation of high‐performance POD fiber, which is of great significance for broadening the application field of POD fibers.

Influences of Ultrasonic Treatments on the Structure and Antioxidant Properties of Sugar Beet Pectin

The objective of this study was to explore the structural changes and oxidation resistance of ultrasonic degradation products of sugar beet pectin (SBP). The changes in the structures and antioxidant activity between SBP and its degradation products were compared. As the ultrasonic treatment time increased, the content of α-D-1,4-galacturonic acid (GalA) also increased, to 68.28%. In addition, the neutral sugar (NS) content, esterification degree (DE), particle size, intrinsic viscosity and viscosity-average molecular weight (MV) of the modified SBP decreased. Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) were used to study the degradation of the SBP structure after ultrasonication. After ultrasonic treatment, the DPPH and ABTS free radical scavenging activities of the modified SBP reached 67.84% and 54.67% at the concentration of 4 mg/mL, respectively, and the thermal stability of modified SBP was also improved. All of the results indicate that the ultrasonic technology is an environmentally friendly, simple, and effective strategy to improve the antioxidant capacity of SBP.

A novel bisphenol A‐free polyarylates synthesis strategy: 4,4′‐sulfobisphenol/2,2‐bis(4‐hydroxyphenyl)butane co‐polyarylate prepared by interfacial polymerization

AbstractA series of bisphenols, 4,4′‐sulfobisphenol (BPS)/2,2‐bis(4‐hydroxyphenyl)butane (BPB) co‐polyarylates with amorphous structures were synthesized from two BPS and BPB, and two different structures of benzoyl chloride monomers. The results of DFT calculations showed that the reaction activation energy of BPB with isophthaloyl chloride (IPC) and terephthaloyl chloride (TPC) was 8.05–8.40 Kcal/mol. The reaction activation energy of BPS with IPC and TPC was 38.73–39.09 Kcal/mol. GPC test results were consistent with theoretical calculations with BPS content from 0% to 15% resulting in a copolymer Mn of 22,000–11,600 and a Mw of 46,100–34,800. The intrinsic viscosity of co‐polyarylates ranged from 0.55 to 0.71 dL/g. The glass transition temperature (Tg) and 5% thermal weight loss of the co‐polyarylates were 179.3–205.4 °C and 461.4–487.8 °C, respectively. Improved solubility of co‐polyarylates in polar solvents. At the same time, the introduction of BPS did not result in any loss of mechanical properties, with Young's modulus in the range of 1444.32–1870.45 MPa, elongation at break in the range of 23.7%–30.8%, and tensile strength in the range of 52.21–59.38 MPa.

Solid State Polymerization of Biodegradable Poly(butylene sebacate-co-terephthalate): A Rapid, Facile Method for Property Enhancement.

Poly(butylene sebacate-co-terephthalate) (PBSeT) has generated attention as a promising biopolymer for preparing bioplastics. However, there are limited studies on the synthesis of PBSeT, impeding its commercialization. Herein, with a view to addressing this challenge, biodegradable PBSeT was modified using solid state polymerization (SSP) with various ranges of time and temperature. The SSP used three different temperatures below the melting temperature of PBSeT. The polymerization degree of SSP was investigated using Fourier-transform infrared spectroscopy. The changes in the rheological properties of PBSeT after SSP were investigated using a rheometer and an Ubbelodhe viscometer. Differential scanning calorimetry and X-ray diffraction showed that the crystallinity of PBSeT was higher after SSP. The investigation revealed that after SSP for 40 min at 90 °C, PBSeT exhibited higher intrinsic viscosity (increased from 0.47 to 0.53 dL/g), crystallinity, and complex viscosity than PBSeT polymerized at other temperatures. However, a high SSP processing time resulted in a decrease in these values. In this experiment, SSP was most effectively performed in the temperature range closest to the melting temperature of PBSeT. This indicates that SSP could be a facile and rapid method for improving the crystallinity and thermal stability of synthesized PBSeT.

New Facet in Viscometry of Charged Associating Polymer Systems in Dilute Solutions

The peculiarities of viscosity data treatment for two series of polymer systems exhibiting associative properties: brush-like amphiphilic copolymers-charged alkylated N-methyl-N-vinylacetamide and N-methyl-N-vinylamine copolymer (MVAA-co-MVACnH2n+1) and charged chains of sodium polystyrene-4-sulfonate (PSSNa) in large-scale molecular masses (MM) and in extreme-scale of the ionic strength of solutions were considered in this study. The interest in amphiphilic macromolecular systems is explained by the fact that they are considered as micellar-forming structures in aqueous solutions, and these structures are able to carry hydrophobic biologically active compounds. In the case of appearing the hydrophobic interactions, attention was paid to discussing convenient ways to extract the correct value of intrinsic viscosity η from the combined analysis of Kraemer and Huggins plots, which were considered as twin plots. Systems and situations were demonstrated where intrachain hydrophobic interactions occurred. The obtained data were discussed in terms of lnηr vs. cη plots as well as in terms of normalized scaling relationships where ηr was the relative viscosity of the polymer solution. The first plot allowed for the detection and calibration of hydrophobic interactions in polymer chains, while the second plot allowed for the monitoring of the change in the size of charged chains depending on the ionic strength of solutions.

Therapeutic phosphorodiamidate morpholino oligonucleotides: Physical properties, solution structures, and folding thermodynamics

Elucidating the structure-function relationships for therapeutic RNA mimicking phosphorodiamidate morpholino oligonucleotides (PMOs) is challenging due to the lack of information about their structures. While PMOs have been approved by the US Food and Drug Administration for treatment of Duchenne muscular dystrophy, no structural information on these unique, charge-neutral, and stable molecules is available. We performed circular dichroism and solution viscosity measurements combined with molecular dynamics simulations and machine learning to resolve solution structures of 22-mer, 25-mer, and 30-mer length PMOs. The PMO conformational dynamics are defined by the competition between non-polar nucleobases and uncharged phosphorodiamidate groups for shielding from solvent exposure. PMO molecules form non-canonical, partially helical, stable folded structures with a small 1.4- to 1.7-nm radius of gyration, low count of three to six base pairs and six to nine base stacks, characterized by -34 to -51kcal/mol free energy, -57 to -103kcal/mol enthalpy, and -23 to -53kcal/mol entropy for folding. The 4.5- to 6.2-cm3/g intrinsic viscosity and Huggins constant of 4.5-9.9 are indicative of extended and aggregating systems. The results obtained highlight the importance of the conformational ensemble view of PMO solution structures, thermodynamic stability of their non-canonical structures, and concentration-dependent viscosity properties. These principles form a paradigm to understand the structure-properties-function relationship for therapeutic PMOs to advance the design of new RNA-mimic-based drugs.