Variable Temperature FTIR Research Articles

“Co-coordination force” assisted rigid-flexible coupling crystalline polymer for high-performance aqueous zinc-organic batteries

Organic electrode materials (OEMs) have attracted substantial attention for aqueous zinc-ion batteries (AZIBs) due to their advantages in relieving resource and environmental anxiety. However, the potential of OEMs is plagued by their low achievable capacity and high solubility. Here, we have proposed a new concept of “co-coordination force” and designed a rigid-flexible coupling crystalline polymer that can overcome the abovementioned limitations. The obtained crystalline polymer (BQSPNs) with multiredox centres makes the BQSPNs exist intermolecular hydrogen bonds (HB) among -C=O, -C=N, and -NH and consequently exhibits transverse two-dimensional arrays and longitudinal π-π stacking structure. Additionally, in-situ FTIR, Raman, variable temperature FTIR spectra, and 2D nuclear overhauser effect spectroscopy (NOESY) well capture the existence and evolution process of HB during the electrochemistry reaction process of BQSPNs, uncovering the effect of HB in stabilizing the structure and promoting the reaction kinetics. As a result, the BQSPNs with rationally designed “co-coordination force” deliver a high capacity of 459.6 mAh/g and a stable cycling lifetime for more than 100,000 cycles at 10 A/g in AZIBs. Our results disclose the HB effect and provide a brand-new strategy for high-performance OEMs design.

Features of Wax Appearance Temperature Determination of Waxy Crude Oil Using Attenuated Total Reflection Fourier Transform Infrared Spectroscopy Under Ambient and High Pressure.

The wax appearance temperature (WAT), being one of the key characteristics of waxy crude oil and other waxy substances, is used for the necessary assessment of the phase stability of materials during various technological processes. However, the determination of this parameter as well as peculiarities of wax formation under high gas pressure suffers from the lack of suitable techniques for this task. To address this issue, an attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR) method has been applied for the first time to measure the WAT of waxy crude oil under high gas pressure. Carbon dioxide (CO2), nitrogen, and natural gas were used in the study due to their widespread applicability as injection gases in enhanced oil recovery methods. The S2/S1 versus temperature method based on changes in the band of rocking vibrations of the CH2 group was applied to determine WAT. It was found that the ATR FT-IR method based on the proposed dependence S2/S1 versus temperature gives lower WAT values compared to those observed by viscometry, magnetic resonance imaging inspection, and cross-polarized microscopy methods for the waxy crude oil studied. A detailed analysis was carried out using variable-temperature ATR FT-IR spectra of waxy crude oil in the temperature region near the WAT. Essentially different dynamics of wax crystal formation in waxy oil sample and model paraffin solution were demonstrated during the cooling process. The results obtained by high-pressure ATR FT-IR showed that CO2 and natural gas reduce the WAT, while nitrogen has virtually no effect. In addition, for the studied oil, it was found that high pressure of CO2 and natural gases leads to a visual decrease in the amount of wax crystals precipitated, but not to the complete disappearance of microcrystals at a certain temperature and pressure. The results obtained proved that ATR FT-IR can be an effective method for proper determinations of WAT under high-pressure conditions similar to those met in practice.

Stability of Quadruple Hydrogen Bonds in an Ionic Liquid Environment.

Hydrogen bonds (H-bonds) are highly sensitive to the surrounding environments owing to their dipolar nature, with polar solvents kown to significantly weaken H-bonds. Herein, the stability of the H-bonding motif ureidopyrimidinone (UPy) is investigated, embedded into a highly polar polymeric ionic liquid (PIL) consisting of pendant pyrrolidinium bis(trifluoromethylsulfonyl)imide (IL) moieties, to study the influence of such ionic environments on the UPy H-bonds. The content of the surrounding IL is changed by addition of an additional low molecular weight IL to further boost the IL content around the UPy moieties in molar ratios of UPy/IL ranging from 1/4 up to 1/113, thereby promoting the polar microenvironment around the UPy-H-bonds. Variable-temperature solid-state MAS NMR spectroscopy and FT-IR spectroscopy demonstrate that the UPy H-bonds are largely present as (UPy-) dimers, but sensitive to elevated temperatures (>70°C). Subsequent rheology and DSC studies reveal that the ILs only solvate the polymeric chains but do not interfere with the UPy-dimer H-bonds, thus accounting for their high stability and applicability in many material systems.

Self‐healing and reprocess of crosslinked polyurethane based on dynamic oxime‐carbamate bond

AbstractPolymer materials containing oxime‐carbamate bonds show superior self‐healing ability under certain conditions. In this study, a series of dynamic oxime‐carbamate based PU‐D‐x (Polyurethane‐Dimethylglyoxime‐x) with different crosslinking degrees (x indicates the content of crosslinker based on the weight of solid content) were prepared, and the self‐healing together with the reprocessing characteristic was investigated. In situ variable temperature FTIR spectroscopy shows that the dissociation of oxime‐carbamate bonds occurred at 80°C and can be accelerated by the increasing temperature. With relatively lower cross‐linking degrees, these types of PU can be healed at low temperature and in a short time, for example, PU‐D‐0.3 can be completely healed at 80°C in 6 h, and PU‐D‐0.45 can be almost completely healed at 80°C in 9 h. With the increase of cross‐linking degree, the self‐repair of this kind of PU needs to be carried out at higher temperature and needs an extension of time. However, when the temperature increased to 100°C, the self‐healing time is greatly reduced to 3–5 h. Most interestingly, these types of crosslinked PUs showed expected reusing and reprocessing characteristics, even the PU‐D‐1.2 sample with the highest crosslinking degree can be completely reshaped and reprocessed under 120°C and 10 MPa pressure.

Effects of montmorillonite (MMT) on the crystallization behavior of poly(L-lactic acid) (PLLA) by variable-temperature FTIR coupled with difference spectrometry, PCMW2D and 2DCOS analyses

Effects of montmorillonite (MMT) on the crystallization behavior of poly(L-lactic acid) (PLLA) were investigated by variable-temperature FTIR spectroscopy. The variations of carbonyl band (1800–1720 cm−1) of different PLLA/MMT nanocomposites were focused due to its strong intensity and the involved abundant structure information. Difference spectrometry was used to evaluate the structural variations of PLLA after introducing MMT, and perturbation correlation moving window two-dimensional analysis (PCMW2D) split the temperature range into two sub-regions, i.e., 32–116 ℃ and 116–152 ℃, on the basis of the spectral variation. Two-dimensional correlation spectroscopy (2DCOS) was further applied to such sub-regions in order to find the change order between varied PLLA polymorphs. The results showed that less addition of MMT (≤3%) would lead to a well-exfoliated structure, which not only had no nucleation effect for PLLA, but also delayed the cold crystallization to a higher temperature compared with the one of pure PLLA. However, a higher addition of MMT (≥5%) would lead to an intercalated structure, which acted as a nucleating agent and thus advanced the cold crystallization to a lower temperature. Nevertheless, the introduction of MMT cannot affect the phase transition order between the amorphous, the intermediate, the α′- and the α′-PLLAs based on 2DCOS results.

Tunable Thermo-Responsive Properties of Hydroxybutyl Chitosan Oligosaccharide.

In this study, a simple method was used to synthesize novel thermosensitive hydroxybutyl chitosan oligosaccharide (HBCOS) by introducing hydroxybutyl groups to C6–OH of chitosan oligosaccharide (COS) chain. The variation in light scattering demonstrated that HBCOS had good thermosensitive properties and the particle size of HBCOS changed from 2.21–3.58 to 281.23–4,162.40 nm as the temperature increased to a critical temperature (LCST). The LCST of HBCOS (10 mg/ml) decreased from 56.25°C to 40.2°C as the degrees of substitution (DSs) increased from 2.96 to 4.66. The LCST of HBCOS with a DS of 4.66 decreased to 33.5°C and 30°C as the HBCOS and NaCl concentrations increased to 50 mg/ml and 4% (w/v), respectively. Variable-temperature FTIR spectroscopy confirmed that dehydration of hydrophobic chains and the transition of hydrogen bonds were the driving forces for the phase transition of HBCOS. Moreover, HBCOS was not cytotoxic at different concentrations. This work generated a novel thermosensitive HBCOS with tunable thermoresponsive properties and excellent biocompatibility, which may be a potential nanocarrier for the biomedical application.

0D + 1D = 1D Zn-orotate-Bimb polyrotaxane coordination polymer: Synthesis, structure, thermogravimetric and variable temperature luminescence analysis

A new polyrotaxane coordination polymer {[Zn(Or)(Bimb)(H2O)]2·6H2O}n(1) has been synthesized using Zn(II) ion with 1,4-bis[(1H-imidazol-1-yl)methyl]benzene) (Bimb) and potassium orotate (OrK) ligands at ambient temperature. Single-crystal X-ray diffraction, elemental analysis, variable temperature Powder X-ray diffraction (VT-PXRD), variable temperature FTIR (VT-FTIR) and TG/DT/TDG were used to characterize the complex. Complex (1) contains 0D binuclear Zn(1)–based molecular “loop”, 1D Zn(2)–based molecular “string” yielding to 0D + 1D = 1D polyrotaxane coordination polymers. Supramolecular network in complex (1) is stabilized by classical strong NH∙∙∙O and OH∙∙∙O hydrogen bonds resulting in the formation of 2D inter-layer polyrotaxane coordination polymers and 3D supramolecular network via these non-covalent interactions. The solid-state variable temperature-luminescence studies of as synthesized and heated forms of (1) emit strong luminescence in the range of 363–439 nm (2.82–3.41 eV) with slight contrast in physical façade. The thermal breakdown of (1) yielded spherical shaped ZnO nanoparticles with diameters of ̴ 32 nm, as confirmed by FESEM, EDAX.

Curing mechanism of resole phenolic resin based on variable temperature FTIR spectra and thermogravimetry-mass spectrometry

To solve the problem that the curing mechanism evolution of phenolic resin catalyzed by Ba(OH)2 remained unclear, the p-p methylene index, o-p methylene index, o-o methylene index, hydroxymethyl index, and ether index were introduced to quantitatively investigate the chemical structure of resin in the curing temperature range of 90–230°C. The chemical structures were investigated by variable temperature FT-IR. The gas products released with the increase of curing temperature were characterized by Thermogravimetry-Mass Spectrometry. The curing mechanism from 90°C to 230°C was concluded finally. The results show that the main reaction is the formation of the p-p methylene group in the range of 90–120°C. It is difficult to form the o-p methylene bridge at this stage. In the range of 120–160°C, the main reaction is the formation of the p-p methylene group. From 160°C to 190°C, the main reactions are the breaking of the ether bond, the formation of the carbonyl group and the propyl bridge. Above 190°C, the main reactions are polycondensation reaction among phenolic hydroxyl groups, and the formation reaction of carbonyl groups. The ether bond breaks completely above 230°C. This work provides a new method to investigate the curing mechanism. It is a benefit for the rational design of the curing process of phenolic resin-based composites.

Properties tuning of supramolecular discotics by non-mesogenic triazines and acids

In this work, a new series of supramolecular discotic liquid crystals induced by hydrogen bonding between triazines T x and aromatic acids A y are presented, most of which exhibit columnar mesomorphic properties. The design strategy of combining the hydrogen bond parallel to the molecular plane with the π-stacking trend of triazine derivatives and aromatic acids was utilized, which has been widely confirmed by nematic, smectic or columnar liquid crystal phases. The formation of hydrogen bonded complexes was proven by FT-IR and 1H NMR spectroscopy and their stability studied by variable temperature FT-IR techniques. All prepared hydrogen bonded complexes displayed mesogenic properties and their liquid crystalline properties were investigated by means of DSC, POM and XRD. This work provides useful information to assist our further design of hydrogen bonded supramolecular liquid crystals for optoelectronic applications.

Anion-Dependent Electron Transfer in the Cyanide-Bridged [Fe2Co2] Capsules.

A family of molecular capsules, {[(Tp*)Fe(CN)3Co(bpyC═N(CH2)7N═Cbpy)]2[X]2}·sol (1, X = ClO4, sol = 6DMF; 2, X = PF6, sol = 6DMF; 3, X = OTf, sol = 6DMF; 4, X = BPh4, sol = 2DMF; Tp* = hydrotris(3,5-dimethylpyrazol-1-yl)borate; bpy = 2,2'-bipyridine), were prepared via the Schiff-base condensation of the aldehyde-substituted bpy (bpyCHO) and 1,7-diaminoheptane (H2N(CH2)7NH2). All the complexes contain the same cyanide-bridged cationic square cores ([Fe2Co2]2+), which are encapsuled by the flexible alkyl chains. Variable-temperature single-crystal X-ray diffraction, FT-IR spectra, and magnetic studies reveal the abrupt and complete, thermo- and photo-induced electron-transfer-coupled spin transition for 1-3, while the pure high-spin phase for 4. Such distinct behavior is attributed to the effective long-range cooperative interactions mediated by the intercluster π-π couplings in 1-3, which, however, are significantly blocked in 4 due to the steric effect of interstitial BPh4- anions. Furthermore, the shift in the thermally induced transition temperatures of 254 K for 1, 233 K for 2, and 187 K for 3, respectively, is likely correlated to the variable H···O and H···F interactions between the solvent molecules, anions, and the bipyridine ligands of the [Fe2Co2] squares, suggesting the significant anion-dependent effect in such a system.

Ultrahigh Flux and Strong Affinity Poly(N-vinylformamide)-Grafted Polypropylene Membranes for Continuous Removal of Organic Micropollutants from Water.

The rapid and effective removal of organic micropollutants (OMPs) from water remains a huge challenge for traditional water treatment techniques. Compared with powder adsorbents such as polymers and nanomaterials, the free-standing adsorptive membrane is possible for large-scale applications and shows promise in removing OMPs. Herein, inspired by aquatic plants, a novel free-standing adsorptive membrane (NPPM) with high water flux, strong adsorption affinity, and excellent reproducibility was prepared by one-step UV surface grafting. N-Vinylformamide (NVF) was employed to introduce multiple hydrophilic and hydrogen bonding sites on the surface of commercial polypropylene fiber membranes (PPM). The NPPM exhibits excellent water permeability and ultrahigh water flux (up to 40 000 L/(m2 h)) and could continuously remove a broad spectrum of OMPs from water. Its adsorption performance is 5-100 times higher than that of PPM and commercial membranes. Even in natural water sources such as tap water and river water, the NPPM shows unchanged adsorption performance and high OMPs removal efficiency (>95%). Notably, the NPPM has excellent regeneration performance and can be regenerated by hot water elution, which provides an environmentally friendly regeneration method without involving any organic solvent. Moreover, the synergy between hydrogen bonding and hydrophobic interaction is revealed, and the hydrophobic interaction provided by the hydrophobic substrate is proved to play a fundamental role in OMPs adsorption. The strong hydrogen bonds between the grafts and the OMPs are demonstrated by variable-temperature FTIR spectroscopy (vt-FTIR), 13C nuclear magnetic resonance spectroscopy (13C NMR), and simulation calculations. The strong hydrogen bonds could increase the enthalpy change and enhance the adsorption affinity, so the NPPM has a strong adsorption affinity, which is 100 times that of similar adsorption membranes. This study not only presents an adsorptive membrane with great commercial potential in the rapid remediation of a water source but also opens a pathway to develop an adsorptive membrane with high water flux and strong adsorption affinity.

Recovery of Fuels Using the Supramolecular Gelation Ability of a Hydroxybenzoic Acid Bisamide Derivative

In order to remedy the environmental pollution caused by oil spills, new materials with gelation capacity of organic solvents and fuels have been synthetized during the recent years. Among them, some of the most promising materials contain amide groups, which are often incorporated into the chemical structure of organogelators due to their effectiveness in gelling organic solvents through hydrogen bonds. A bisamide derivative of hydroxybenzoic acid (Bis-HUB1) was designed and synthesized in two steps and is able to congeal organic solvents. Gelation tests, critical gelation concentrations, and gel-sol transition temperatures were discussed in terms of its supramolecular interactions. Intermolecular hydrogen bonds and π-π stacking were studied through variable-temperature FTIR and UV-visible spectroscopy, while the structural characterization was performed via freeze-fracture TEM. Interestingly, Bis-HUB1 showed the ability to gel gasoline and diesel from monophasic and biphasic systems, which implies its potential use as a remediation agent in fuel spills. The results encourage further research.

Variable temperature FTIR spectra of polycrystalline purine nucleobases and estimating strengths of individual hydrogen bonds

In the first part of this work, we report the FTIR spectra of pure NH and isotopically substituted ND (10–15% D and 80–90% D) polycrystalline hypoxanthine, xanthine, adenine and guanine recorded in the 400–4000 cm−1 range, as a function of temperature (10–300 K). We provide assignments of the stretching and out-of-plane bending amine (NH2) and imine (NH) bands to the distinct H-bonds present in the crystal, based on the temperature sensitivity and isotopic exchange behavior. Empirical correlations between spectral and thermodynamic or structural parameters enabled us to estimate the energies and lengths of H-bonds in the studied nucleobase crystals and to correlate them with literature data. The empirical H-bonding energies are compared with H-bonding and stacking energies computed for hypoxanthine.In the second part, strategies for using the empirical correlations together with information extracted from quantum mechanical data (in particular from the Bader’s quantum theory of atoms in molecules, QTAIM) for the evaluation of hydrogen bonding properties are discussed, and their advantages and drawbacks pointed out. The justification for a cooperative use of quantum-mechanical calculations with empirical spectra-energy correlations is discussed.

Triazole Linked N-Acetylglucosamine Based Gelators for Crude Oil Separation and Dye Removal.

Marine oil-spills have a long-lasting impact on the environment; therefore, it is a major concern in the scientific community to find a solution for remediation. Recently, phase selective organo-gelators emerged as potential materials for removal of oil from water through selective gelation. Herein, we report synthesis of a series of C-6 triazole linked N-acetylglucosamine derivatives, among which three have shown excellent selective gelation of organic solvents, diesel, petrol, and crude oils in water and seawater. We have studied phase selective gelation against different API grade crude oils (from light to heavy), and the gelation was achieved using nontoxic carrier solvent at room temperature in less than 15 min, and gelators were found useful for recovering crude oils. Critical gel concentration (CGC) of crude oil gelators was found to be 2.3-12% (w/v). The variable temperature NMR and FTIR experiments reveal that intermolecular hydrogen bonding was responsible for gel formation. Furthermore, a gelator was utilized for selective dye removal from water.

Toughness and reinforcement of adipic acid-polyoxypropylene diamine copolymer modified diglycidyl ether of bisphenol-A: Induced by intramolecular hydrogen bonding

A novel soft segment adipic acid-polyoxypropylene diamine copolymer with Mw = ~2000 (AA-PPA 2000) was well obtained through chain extending of bio-based polyoxypropylene diamine D400 using adipic acid (AA). This copolymer was then used to modify the diglycidyl ether of bisphenol A (DGEBA) epoxy/diethyl toluene diamine (DDM) curing system while polyoxypropylene diamine (D2000) was taken as the reference. The variable temperature FTIR (V-FTIR) spectral was used to determine the hydrogen bonds in cured epoxy resins. The crosslinking density of epoxy composites was further checked using the low field nuclear magnetic resonance (NMR) and dynamic mechanical analysis (DMA). Interestingly, SEM images of the fracture surfaces showed that there were many small holes on the fracture surface of D2000 cured composites while rough cracks were observed instead of tiny holes on the fracture surface of AA-PPA2000 modified composites indicating AA-PPA2000 had good compatibility in epoxy composites. All the findings revealed that AA-PPA 2000 was a preferable tougher compared to D2000. Higher crosslinking density was generated in AA-PPA2000 cured epoxy resin due to the formation of intermolecular hydrogen bonds and more complicated networks in the epoxy composites, leading to the synchronous enhancement of strength and fracture toughness.

Multivalent urea bond assembly of polyacrylate oligomers with improved mechanical strength and high self-healing efficiency

The self-healing and stretchable polyacrylate oligomers based on multivalent urea bonds were synthesized through the cross-linking of polyacrylate prepolymers and polyurea trimer. The variable temperature FT-IR and oscillatory rheometer analysis testified the excellent repeatability of multivalent urea bonds. Good thermal stability of the self-healing samples were proved by TGA. The length of the polymer branch and crosslink density of each sample could provide different thermodynamic properties which were confirmed by DSC and DMA. Meanwhile, the cross-linked polyacrylate oligomers without any catalyst or external intervention showed multiple self-repairs, scratch repair capabilities and high self-healing efficiency which was confirmed by the optical microscopy and the stress–strain testing. The maximum tensile strength of the pristine sample was as high as 7.8 MPa. Moreover, the oligomers showed self-repair repeatedly at room temperature and rapidly restored to 95% of the original tensile strength at 50 °C. Thus, the type of cross-linked polyacrylate oligomers might have high potential for further research in medicine, resin and plastics applications.

Tuning of reversible thermochromic properties of salicylaldehyde Schiff bases through the substitution of methoxy and nitro groups

In this study, in order to explore the new kinds of reversible thermochromic materials, four salicylaldehyde Schiff bases (BSP1-4) substituted with methoxy and nitro groups were synthesized and their reversible thermochromic properties were investigated. All compounds were characterized by HNMR, IR, UV–vis, TG-DSC, and SEM techniques. Through HNMR, IR and UV–vis spectra, four target products display different colors. The UV–Vis spectra show that the type and position of the substituents of BSPs can control the absorption wavelength by changing the electronic transition mode, which leads to the difference of the color of the samples. With the increase of light colored samples, the content of the ΔE1 gradually increases until the maximum value of 48.6. TG-DSC result indicates good thermal stability of the BSP below 350 °C. SEM images show that the surface morphologies of four BSP samples are different, including flake, rod and strip. The thermochromic properties of the BSP samples were evaluated using variable temperature FT-IR spectroscopic, solid UV–Vis spectra and response time. DFT calculations were conducted to rationalize the optical behavior of the BSP samples in Enol and Ketone form. The results of variable temperature FT-IR support the hypothesis that the reversible thermochromic mechanism of salicylaldehyde Schiff base is proton transfer. Among all of BSPs, the BSP1 has the best reversible thermochromic cycle stability (ΔE2 = 2.6) and the shortest response time (10s) which can be used as the new promising thermochromism materials.

Preparation and Properties Analysis of Chlorinated Butyl Rubber (CIIR)/Organic Diatomite Damping Composites.

In this work, a novel type of diatomite was prepared with a limited content of hindered phenol groups grafted on its hydrophobic surface. The obtained samples were characterized for their surface groups, particle morphology, pore structure, and thermal behaviors. Then, modified diatomite (MDT) was used in preparation of reinforced chlorinated butyl rubber (CIIR) composites by mechanical blending method. The powder of MDT can be uniformly dispersed in CIIR matrices and the compatibility was good. In addition, the MDT showed a positive effect on damping performance of CIIR composites. A blending ratio of CIIR/MDT = 100/10 presented the best damping performance and the damping temperature range (tan δ > 0.7) was extended from 60 to 70 °C. The variable temperature FTIR spectra showed the presence of hydrogen bonds between the hydroxyl groups and chloride atoms in the CIIR matrices, and a blue shift exhibited when these hydrogen bonds were dissociated. Hence, these CIIR composites provided good damping behaviors and supplied a novel and promising way for preparation of high damping rubber composites with broad temperature ranges.

Comprehensive Insight into the Hydrogen Bonding of Silanes

The interaction of a set of mono-, di- and trisubstituted silanes with OH proton donors of different strength was studied by variable temperature (VT) FTIR and NMR spectroscopies at 190-298 K. Two competing sites of proton donors coordination: SiH and π-density of phenyl rings-are revealed for phenyl-containing silanes. The hydrogen bonds SiH⋅⋅⋅HO and OH⋅⋅⋅π(Ph) are of similar strength, but can be distinguished in the νSiH range: the νSiH⋅⋅⋅HO vibrations appear at lower frequencies while OH⋅⋅⋅π(Ph) complexes give Si-H vibrations shifted to higher frequency. The calculations showed the manifold picture of the noncovalent interactions in hydrogen-bonded complexes of phenylsilanes. As OH⋅⋅⋅HSi bonds are weak, the other noncovalent interactions compete in the stabilization of the intermolecular complexes. Still, the structural and electronic parameters of "pure" DHB complexes of phenylsilanes are similar to those of Et3 SiH.

Synthesis of urea‐containing ABA triblock copolymers: Influence of pendant hydrogen bonding on morphology and thermomechanical properties

ABSTRACTReversible addition‐fragmentation chain transfer (RAFT) polymerization produced novel ABA triblock copolymers with associative urea sites within pendant groups in the external hard blocks. The ABA triblock copolymers served as models to study the influence of pendant hydrogen bonding on polymer physical properties and morphology. The triblock copolymers consisted of a soft central block of poly(di(ethylene glycol) methyl ether methacrylate) (polyDEGMEMA, 58 kg/mol) and hard copolymer external blocks of poly(2‐(3‐hexylureido)ethyl methacrylate‐co‐2‐(3‐phenylureido)ethyl methacrylate) (polyUrMA, 18‐116 kg/mol). Copolymerization of 2‐(3‐hexylureido)ethyl methacrylate (HUrMA) and 2‐(3‐phenylureido)ethyl methacrylate (PhUrMA) imparted tunable hard block Tg's from 69 to 134 °C. Tunable hard block Tg's afforded versatile thermomechanical properties for diverse applications. Dynamic mechanical analysis (DMA) of the triblock copolymers exhibited high modulus plateau regions (∼100 MPa) over a wide temperature range (−10 to 90 °C), which was indicative of microphase separation. Atomic force microscopy (AFM) confirmed surface microphase separation with various morphologies. Variable temperature FTIR (VT‐FTIR) revealed the presence of both monodentate and bidentate hydrogen bonding, and pendant hydrogen bonding remained as an ordered structure to higher than expected temperatures. This study presents a fundamental understanding of the influence of hydrogen bonding on polymer physical properties and reveals the response of pendant urea hydrogen bonding as a function of temperature as compared to main chain polyureas. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1844–1852