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Atomic force microscopy (AFM) can be used to quantitatively study nanomaterials in different media, e.g. vacuum, air, or submerged in a liquid. A technique was developed to study swelling of individual cellulose nanofibrils (CNFs) using AFM. As a case study, CNFs with different degrees of crystallinity (DoC) were examined for swellability going from dry to wet (submerged in de-ionized water). Swelling was found to depend on DoC, but no significant correlation between fibril diameter and swellability was seen. Upon introduction of de-ionized water high DoC samples ( $$65\pm 2\%$$ 65 ± 2 % ) were found to have a diameter increase of 34% on average, whereas low DoC ( $$44\pm 2\%$$ 44 ± 2 % ) were found to have a diameter increase of 44% on average. A tested control, consisting of platinum nanowires on silisium, did not swell. Graphic abstract
Vegar Ottesen; Kristin Syverud. Swelling of individual cellulose nanofibrils in water, role of crystallinity: an AFM study. Cellulose 2020, 28, 19 -29.
AMA StyleVegar Ottesen, Kristin Syverud. Swelling of individual cellulose nanofibrils in water, role of crystallinity: an AFM study. Cellulose. 2020; 28 (1):19-29.
Chicago/Turabian StyleVegar Ottesen; Kristin Syverud. 2020. "Swelling of individual cellulose nanofibrils in water, role of crystallinity: an AFM study." Cellulose 28, no. 1: 19-29.
The influence of cellulose crystallinity on mechanical properties of cellulose nano-fibrils (CNF) was investigated. Degree of crystallinity (DoC) was modified using liquid anhydrous ammonia. Such treatment changes crystal allomorph from cellulose I to cellulose III, a change which was reversed by subsequent boiling in water. DoC was measured using solid state nuclear magnetic resonance (NMR). Crystalline index (CI) was also measured using wide angle X-ray scattering (WAXS). Cotton linters were used as the raw material. The cotton linter was ammonia treated prior to fibrillation. Reduced DoC is seen to associate with an increased yield point and decreased Young modulus. Young modulus is here defined as the maximal slope of the stress–strain curves. The association between DoC and Young modulus or DoC and yield point are both statistically significant. We cannot conclude there has been an effect on strainability. While mechanical properties were affected, we found no indication that ammonia treatment affected degree of fibrillation. CNF was also studied in air and liquid using atomic force microscopy (AFM). Swelling of the nanofibers was observed, with a mean diameter increase of 48.9%.
Vegar Ottesen; Per Tomas Larsson; Gary Chinga-Carrasco; Kristin Syverud; Øyvind Weiby Gregersen. Mechanical properties of cellulose nanofibril films: effects of crystallinity and its modification by treatment with liquid anhydrous ammonia. Cellulose 2019, 26, 6615 -6627.
AMA StyleVegar Ottesen, Per Tomas Larsson, Gary Chinga-Carrasco, Kristin Syverud, Øyvind Weiby Gregersen. Mechanical properties of cellulose nanofibril films: effects of crystallinity and its modification by treatment with liquid anhydrous ammonia. Cellulose. 2019; 26 (11):6615-6627.
Chicago/Turabian StyleVegar Ottesen; Per Tomas Larsson; Gary Chinga-Carrasco; Kristin Syverud; Øyvind Weiby Gregersen. 2019. "Mechanical properties of cellulose nanofibril films: effects of crystallinity and its modification by treatment with liquid anhydrous ammonia." Cellulose 26, no. 11: 6615-6627.
Due to the high specific surface area, high mechanical strength and broad possibility of surface modification, nanocellulose has obtained much attention as a new class of bio-based nanomaterials with promising potential in a wide variety of applications. Recently, a considerable amount of research has been aimed to the fabrication of nanocellulose based hybrid membranes for water treatment. However, nanocellulose based hybrid gas separation membrane is still a new research area. Herein, we force on recent advancements in the fabrication methods and separation performances of nanocellulose-based hybrid membranes for CO2 separation, the transport mechanisms involved, along with the challenges in the utilization of nanocellulose in membranes. Finally, some perspectives on future R&D of nanocellulose-based membranes for CO2 separation are proposed.
Zhongde Dai; Vegar Ottesen; Jing Deng; Ragne M. Lilleby Helberg; Liyuan Deng. A Brief Review of Nanocellulose Based Hybrid Membranes for CO2 Separation. Fibers 2019, 7, 40 .
AMA StyleZhongde Dai, Vegar Ottesen, Jing Deng, Ragne M. Lilleby Helberg, Liyuan Deng. A Brief Review of Nanocellulose Based Hybrid Membranes for CO2 Separation. Fibers. 2019; 7 (5):40.
Chicago/Turabian StyleZhongde Dai; Vegar Ottesen; Jing Deng; Ragne M. Lilleby Helberg; Liyuan Deng. 2019. "A Brief Review of Nanocellulose Based Hybrid Membranes for CO2 Separation." Fibers 7, no. 5: 40.
Vegar Ottesen; Vinay Kumar; Martti Toivakka; Gary Chinga Carrasco; Kristin Syverud; Øyvind W. Gregersen. Viability and properties of roll-to-roll coating of cellulose nanofibrils on recycled paperboard. Nordic Pulp & Paper Research Journal 2017, 32, 1 .
AMA StyleVegar Ottesen, Vinay Kumar, Martti Toivakka, Gary Chinga Carrasco, Kristin Syverud, Øyvind W. Gregersen. Viability and properties of roll-to-roll coating of cellulose nanofibrils on recycled paperboard. Nordic Pulp & Paper Research Journal. 2017; 32 (2):1.
Chicago/Turabian StyleVegar Ottesen; Vinay Kumar; Martti Toivakka; Gary Chinga Carrasco; Kristin Syverud; Øyvind W. Gregersen. 2017. "Viability and properties of roll-to-roll coating of cellulose nanofibrils on recycled paperboard." Nordic Pulp & Paper Research Journal 32, no. 2: 1.
Vegar Ottesen; Kristin Syverud; Øyvind W. Gregersen. Mixing of cellulose nanofibrils and individual furnish components: Effects on paper properties and structure. Nordic Pulp & Paper Research Journal 2016, 31, 1 .
AMA StyleVegar Ottesen, Kristin Syverud, Øyvind W. Gregersen. Mixing of cellulose nanofibrils and individual furnish components: Effects on paper properties and structure. Nordic Pulp & Paper Research Journal. 2016; 31 (3):1.
Chicago/Turabian StyleVegar Ottesen; Kristin Syverud; Øyvind W. Gregersen. 2016. "Mixing of cellulose nanofibrils and individual furnish components: Effects on paper properties and structure." Nordic Pulp & Paper Research Journal 31, no. 3: 1.
In this paper we demonstrate a procedure for preparing bacterial arrays that is fast, easy, and applicable in a standard molecular biology laboratory. Microcontact printing is used to deposit chemicals promoting bacterial adherence in predefined positions on glass surfaces coated with polymers known for their resistance to bacterial adhesion. Highly ordered arrays of immobilized bacteria were obtained using microcontact printed islands of polydopamine (PD) on glass surfaces coated with the antiadhesive polymer polyethylene glycol (PEG). On such PEG-coated glass surfaces, bacteria were attached to 97 to 100% of the PD islands, 21 to 62% of which were occupied by a single bacterium. A viability test revealed that 99% of the bacteria were alive following immobilization onto patterned surfaces. Time series imaging of bacteria on such arrays revealed that the attached bacteria both divided and expressed green fluorescent protein, both of which indicates that this method of patterning of bacteria is a suitable method for single-cell analysis.
Nina Bjørk Arnfinnsdottir; Vegar Ottesen; Rahmi Lale; Marit Sletmoen. The Design of Simple Bacterial Microarrays: Development towards Immobilizing Single Living Bacteria on Predefined Micro-Sized Spots on Patterned Surfaces. PLOS ONE 2015, 10, e0128162 .
AMA StyleNina Bjørk Arnfinnsdottir, Vegar Ottesen, Rahmi Lale, Marit Sletmoen. The Design of Simple Bacterial Microarrays: Development towards Immobilizing Single Living Bacteria on Predefined Micro-Sized Spots on Patterned Surfaces. PLOS ONE. 2015; 10 (6):e0128162.
Chicago/Turabian StyleNina Bjørk Arnfinnsdottir; Vegar Ottesen; Rahmi Lale; Marit Sletmoen. 2015. "The Design of Simple Bacterial Microarrays: Development towards Immobilizing Single Living Bacteria on Predefined Micro-Sized Spots on Patterned Surfaces." PLOS ONE 10, no. 6: e0128162.