Growth of Metal Organic Frameworks on the Surface of Individual Cellulose Nanocrystals

Composites of cellulose nanocrystals (CNCs) and metal organic frameworks (MOFs) are appealing for constructing new materials with applications in catalysts, photonics, gas separation, and environmental remediation. In this paper, the growth of various MOFs on individual CNCs was investigated by varying the growth conditions to obtain a hybrid material, MOF@CNCs. While ZIF-8 and UiO-66 uniformly grew on the surface of CNCs, other common MOFs (e.g., MIL-96, MOF-808, HKUST-1, and MOF-5) exhibited irregular growth patterns. The morphology of the MOF@CNCs materials obtained depended on the metals and ligand used. Furthermore, we investigated the growth of Prussian blue (PB) on CNCs, but we were unable to realize well-defined composites with the framework attached to the surface of CNCs. These investigations are important to realize CNC@MOF composite materials where individual CNCs are functionalized with MOFs

A facile photoinitiated polymerisation route for the preparation of photonic elastomers with chiral nematic order

Photonic crystal elastomers that can change colour upon stretching or compression have potential applications in mechanical sensors and optical coatings. However, facile synthetic strategies are required for these materials to be made on a commercially viable scale. To address this issue, we report a photoinitiated polymerisation method to prepare stretchable chiral nematic cellulose nanocrystal (CNC) elastomer composites that exhibit reversible visible colour upon the application of mechanical stress. The initial CNC-elastomer composite is colourless, but when it is stretched (or compressed), the helical pitch of the chiral nematic structure is reduced to lengths corresponding to the wavelengths of the visible region, resulting in colouration. By increasing the percentage elongation of the material (ca. 50–300%), the structural colour can be tuned from red to blue. The colour of the material was characterised by reflectance optical spectroscopy and reflectance circular dichroism to confirm the wavelength and polarisation of the reflected light.</p

Cellulose Nanocrystal Gels with Tunable Mechanical Properties from Hybrid Thermal Strategies

Gels are useful materials for drug delivery, wound dressings, tissue engineering, and 3D printing. These various applications require gels with different mechanical properties that can be easily tuned, also preferably excluding the use of chemical additives, which can be toxic or harmful to the body or environment. Here, we report a novel strategy to synthesize cellulose nanocrystal (CNC) gels with tunable mechanical properties. Sequential freeze–thaw cycling and hydrothermal treatments were applied to CNC suspensions in different orders to give a series of pristine CNC hydrogels. Freeze-drying of the hydrogels also afforded a series of lightweight CNC aerogels. The mechanical properties of the hydrogels and aerogels were studied by rheological measurements and compression strength tests, respectively. Specifically, the complex modulus of CNC hydrogels ranged from 160 to 32,000 Pa among eight different hydrogels, while Young’s modulus of CNC aerogels was tuned from 0.114 to 3.98 MPa across five different aerogels. The microstructures of aerogels were also investigated by scanning electron microscopy and X-ray microtomography, which revealed remarkable differences between the materials. Solvent sorption–desorption tests showed that the reinforced networks have excellent stability over the basic CNC aerogels in ethanol, demonstrating a material enhancement from the preparation strategies we developed. Thermal conductivity and thermal stability for these materials were also investigated, and it was found that the lowest thermal conductivity was 0.030 W/m K, and all of the aerogels are generally stable below 280 °C. These characteristics also expand the potential applications of this family of CNC gels to lightweight supporting materials and thermal insulators

Cellulose Nanocrystal Gels with Tunable Mechanical Properties from Hybrid Thermal Strategies

Gels are useful materials for drug delivery, wound dressings, tissue engineering, and 3D printing. These various applications require gels with different mechanical properties that can be easily tuned, also preferably excluding the use of chemical additives, which can be toxic or harmful to the body or environment. Here, we report a novel strategy to synthesize cellulose nanocrystal (CNC) gels with tunable mechanical properties. Sequential freeze–thaw cycling and hydrothermal treatments were applied to CNC suspensions in different orders to give a series of pristine CNC hydrogels. Freeze-drying of the hydrogels also afforded a series of lightweight CNC aerogels. The mechanical properties of the hydrogels and aerogels were studied by rheological measurements and compression strength tests, respectively. Specifically, the complex modulus of CNC hydrogels ranged from 160 to 32,000 Pa among eight different hydrogels, while Young’s modulus of CNC aerogels was tuned from 0.114 to 3.98 MPa across five different aerogels. The microstructures of aerogels were also investigated by scanning electron microscopy and X-ray microtomography, which revealed remarkable differences between the materials. Solvent sorption–desorption tests showed that the reinforced networks have excellent stability over the basic CNC aerogels in ethanol, demonstrating a material enhancement from the preparation strategies we developed. Thermal conductivity and thermal stability for these materials were also investigated, and it was found that the lowest thermal conductivity was 0.030 W/m K, and all of the aerogels are generally stable below 280 °C. These characteristics also expand the potential applications of this family of CNC gels to lightweight supporting materials and thermal insulators

Frequency of <i>ROCK2</i> functional polymorphisms.

<p>Abbreviations: MAF, minor allele frequency; 3′-UTR, 3′-untranslated region.</p>a<p>Position is base-pair location in NCBI build 37.1 (GRCh37).</p

Polymorphisms associations with coronary artery disease in our case–control study.

<p>Abbreviations: MAF, minor allele frequency; CI, confidence interval; ORs, odds ratios; ORs (95%CI) and <i>P</i> value were computed with multivariate logistic regression analysis by adjusting for age, sex, BMI, hypertension, diabetes, hyperlipidemia, smoking status, glucose, family history of cardiovascular diseases and renal function.</p

Sequence of probes and primers sets or relative order information.

<p>Abbreviations: FAM, 6-carboxyfluorescein; HEX, hexachloro-6-carboxyfluorescein; MGB, minor groove binder probe.</p

Association between <i>ROCK2</i> polymorphisms and blood pressure values in 927 health control subjects.

<p>Abbreviations: SBP, systolic blood pressure; DBP, Diastolic blood pressure; <i>P</i> value of the blood pressure levels was calculated by multiple linear regression model adjusted for age, sex, BMI and smoking status; A recessive model was used for rs56304104 (MAF <5%), and an additive model was used for rs978906 and rs2230774 (MAF >5%).</p