Wim Thielemans

• PhD, Ir
• Professor at KU Leuven

Water-soluble products derived from biomass processing hold significant potential to enhance biorefinery viability due to their versatile applications. However, their use in the modification of paper products remains underexplored. Here, corn stover and sugarcane bagasse provided water-soluble products being incorporated into high-yield eucalyptus...

Cellulosic materials make up a significant fraction of the current radioactive waste. During storage and disposal, both radiolytic and hydrolytic degradation of such materials can be expected, the latter triggered by the highly alkaline cementitious environment of the waste matrix and disposal facility. The combination of both degradation processes...

Nucleation, the pivotal first step of crystallization, governs essential characteristics of crystallization products, including size distribution, morphology, and polymorphism. While understanding this process is paramount to the design of chemical, pharmaceutical and industrial production processes, major knowledge gaps remain, especially with res...

Nucleation, the pivotal first step of crystallization, governs the essential characteristics of crystallization products, including size distribution, morphology, and polymorphism. While understanding this process is paramount to the design of chemical, pharmaceutical, and industrial production processes, major knowledge gaps remain, especially wit...

Molecular weight decrease caused by thermal, hydrolytic, and mechanical degradation of PLA is a major concern during melt processing. Modeling and predicting degradation is essential to minimize material deterioration and material property changes. Current kinetic degradation models show potential to describe degradation, but they are limited to rh...

Single layered metal–organic coordination networks (MOCNs) are gaining attention thanks to their unique electronic and magnetic properties. The presence of coordinatively unsaturated metal sites within their structures provides additional binding locations for substrates in catalytic processes. Consequently, MOCNs fabricated on solid surfaces are e...

The aim of this study is to investigate the effect of processing conditions on the degradation of poly(lactic acid) (PLA) during single‐screw extrusion. A 2⁵ full factorial design of experiments was used to systematically screen significant main and interaction effects caused by five processing conditions: the moisture content in the granules (drie...

Cellulose nanocrystals (CNCs) have attracted considerable interest due to their optical properties, though their nonlinear optical behavior remains largely unexplored. In this paper, we investigate the second-order nonlinear optical (SONLO)...

Flocculation followed by gravity sedimentation is a low-cost method for microalgae harvesting. Cationic cellulose nanocrystals (CNCs) are novel flocculants composed of cellulose, a bio-based and abundantly available material. While CNCs yield good separation efficiencies for freshwater microalgae, they are less effective for marine microalgae becau...

Cellulose nanocrystals (CNCs) are bio-based nanoparticles that, under the right conditions, self-align into chiral nematic liquid crystals with a helical pitch. In this work, we exploit the inherent confocal effect of second-harmonic generation (SHG) microscopy to acquire highly resolved three-dimensional (3D) images of the chiral nematic phase of...

Throughout the past decades, amphipathic peptide‐based hydrogels have proven to be promising materials for biomedical applications. Amphipathic peptides are known to adopt β‐sheet configurations that self‐assemble into fibers that then interact to form a hydrogel network. A fundamental understanding of how the peptide sequence alters the structural...

Heavy metal pollution in water is a critical environmental concern, demanding effective remediation techniques. Traditional methods, including ion exchange and adsorption, often rely on inductively coupled plasma (ICP) atomic emission spectroscopy/mass spectrometry (AES/MS) for the indirect and time-consuming measurement of residual metal concentra...

In this work, we report the design and fabrication of a light-addressable, paper-based, nanocomposite scaffold for optical modulation and read-out of in vitro grown cardiac tissue. The scaffold consists of paper cellulose microfibers functionalized with gold nanorods (GNRs) and semiconductor quantum dots (QDs), embedded into a cell-permissive colla...

Different microscopy and scattering methods used in the literature to determine the dimensions of cellulose nanocrystals derived from cotton and bacterial cellulose were compared to investigate potential bias and discrepancies. Atomic force microscopy (AFM), small-angle X-ray scattering (SAXS), depolarized dynamic light scattering (DDLS), and stati...

To control the synthesis of designer catalysts on graphitic materials up to the nanometer scale, methods should be provided that combine both nanoscale characterization and bulk scale experiments. This work...

We describe herein a poly(N-isopropylacrylamide) (PNIPAAm)-cellulose nanocrystals (CNC) hydrogel as thermoresponsive and biocompatible material. The hydrogel was generated with simple and robust mixing without need for complicated derivatization. The composition of the hydrogel was optimized for good stiffening and its biocompatibility was verified...

The dehydrogenation of long-chain alkanes to olefins and alkylaromatics is a challenging endothermic reaction, typically requiring harsh conditions which can lead to low selectivity and coking. More favorable thermodynamics can be achieved by using a hydrogen acceptor, such as ethylene. In this work, the potential of heterogeneous platinum catalyst...

Medical ²²⁵Ac/²¹³Bi radionuclide generators are designed to provide a local supply of the short-lived ²¹³Bi for cancer treatment. However, radiation-induced damage to the sorbents commonly used in such radionuclide generators remains a major concern. In this study, the effects of gamma radiation on AG MP-50 cation exchange resin and sulfonated acti...

Cardiomyocyte beating rate modulation is required in multiple in vitro assays and it is usually done by electrical or optogenetic methods. In this work, we develop and characterize a light-based strategy to modulate the cardiomyocyte beating rate by near-infrared (NIR) controlled plasmonic stimulation. For this purpose, gold nanorods (GNRs) acting...

Ordered hierarchically porous carbons exhibiting micro- and mesopores are state-of-the-art porous structures with extraordinary performance in a range of applications (e.g., electrochemistry, catalysis, water treatment). Nevertheless, they are mostly prepared using petroleum-based chemicals, through resource- and energy-intensive, environmentally u...

We report on the fast reaction kinetics of an imine based 2D polymer (2DP) formed from a single monomer carrying both aldehyde and amine groups. Our results point towards a direct monomer-to-crystalline polymer transition without an amorphous intermediate.

Lignocellulosic materials can be found in a significant fraction of the current low- and intermediate-level radioactive waste. During storage and disposal, radiolytic degradation of such materials can be expected, under oxic or anoxic conditions. This degradation may lead to a significant gas production and changes in the physico-chemical propertie...

This study focuses on the heating stage of the rotational molding process. When the mold wall reaches the tacky temperature, free flowing powder starts to adhere, melt, and sinter. In this work, a new modeling strategy is proposed. Compared with the models found in the literature, the model combines the use of a tacky temperature for the adherence...

Within conventional bifunctional catalysts, active metal sites are associated with metal components, while acid sites are usually localized over oxide supports. The modification of metal sites by halogens provides an opportunity to generate acidity via the heterolytic dissociation of hydrogen directly over metal sites. Herein, we report the results...

This review paper presents an overview of the state of the art on process-induced degradation of poly(lactic acid) (PLA) and the relative importance of different processing variables. The sensitivity of PLA to degradation, especially during melt processing, is considered a significant challenge as it may result in deterioration of its properties. T...

Ordered hierarchically porous carbons exhibiting micro- and mesopores are state-of-the-art porous structures with extraordinary performance in a range of applications (e.g., electrochemistry, catalysis, water treatment). Nevertheless, they are mostly prepared using petroleum-based chemicals, through resource- and energy-intensive, environmentally u...

213Bi is a promising candidate for targeted alpha therapy. However, the search for suitable materials to separate clinically relevant activities of 213Bi from its parent 225Ac remains an ongoing yet critical challenge. This study evaluates sulfonated Norit CA1 (activated carbon) materials (SNCAs) as alternative sorbents for use in 225Ac/213Bi radio...

Hypothesis: The micellization of block copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) is driven by the dehydration of PPO at elevated temperatures. At low concentrations, a viscous solution of isolated micelles is obtained, whereas at higher concentrations, crowding of micelles results in an elastic gel. Alternating PEO-P...

Foreign body response (FBR), inflammation, and fibrotic encapsulation of neural implants remain major problems affecting the impedance of the electrode-tissue interface and altering the device performance. Adhesion of proteins and cells (e.g., pro-inflammatory macrophages, and fibroblasts) triggers the FBR cascade and can be diminished by applying...

Flocculation combined with dissolved air flotation (DAF) is a promising technology for harvesting microalgae; therefore, optimisation of flocculant-DAF operating conditions are frequently explored in laboratory experiments. DAF systems have jars of differing volumes, height to diameter ratios, shapes and materials used to manufacture the jars; thus...

In this contribution, we unravel the transient network topology and elasticity of micellar networks formed by hydrophobically associating multiblock copolymers in aqueous solutions. Unlike studies on conventional triblock copolymers bearing hydrophobic blocks as end groups, our research focuses on alternating poly(ethylene oxide) (PEO) and poly(pro...

Two-dimensional (2D) chirality has been actively studied in view of numerous applications of chiral surfaces such as in chiral resolutions and enantioselective catalysis. Here, we report on the expression and amplification of chirality in hybrid 2D metallosupramolecular networks formed by a nucleobase derivative. Self-assembly of a guanine derivati...

Efficient wound repair is crucial for mammalian survival. Healing of skin wounds is severely hampered in diabetic patients, resulting in chronic non-healing wounds that are difficult to treat. High-mobility group box 1 (HMGB1) is an important signaling molecule that is released during wounding, thereby delaying regenerative responses in the skin. H...

This study examined the potential of recycling deep soil mixing residue (DSMR), a cement-soil waste, as a partial Portland cement substitute. The chemical and mineral compositions of DSMR before and after calcination were determined. For the calcined DSMR blended cement pastes, the compressive strength and phase assemblage (characterized using TGA...

The transition to an eco-friendly circular materials system for garbage collected after use from end-users is a serious matter of concern for current society. One important tool in this challenge to achieve a truly circular economy is the chemical recycling of polymers. It has previously been demonstrated that chemical recycling is a feasible alter...

Organocatalysts for polymerization have known a huge interest over the last two decades. Among them, heterocyclic nitrogen bases are widely used to catalyse the ring-opening polymerization (ROP) of heterocycles such as cyclic carbonates. We have investigated the ring-opening polymerization of trimethylene carbonate (TMC) catalysed by DMAP (4-dimeth...

Natural fibre-based materials offer various advantages compared to synthetic fibres, however their applications are limited mainly due to their hygroscopic properties, which are affected by their chemical composition, microstructure and the porosity of the plant cells of which the fibre is composed. Therefore, this work investigates the hygroscopic...

Polypyrrole (PPy) is wildly used as electrode material in supercapacitors due to its high conductivity, low cost, ease of handling, and ease of fabrication. However, limited capacitance and poor cycling stability hinder its practical application. After developing carboxylated cellulose nanocrystals (CNC-COO⁻) as immobile dopants for PPy to improve...

Adsorptive separation is a promising lower-energy alternative for traditional industrial separation processes. While carbon-based materials have a long history in adsorptive removal of organic contaminants from solution or gas mixtures, separation using an adsorption/desorption protocol is rarely considered. The main drawbacks are the limited contr...

Surface modification of cellulose nanocrystals (CNC) by organocatalysed grafting through ring-opening polymerization (ROP) of trimethylene carbonate was investigated. Organocatalysts including an amidine (DBU), a guanidine (TBD), an amino-pyridine (DMAP) and a phosphazene (BEMP) were successfully assessed for this purpose, with performances in the...

Disease research and drug screening platforms require in vitro model systems with cellular cues resembling those of natural tissues. Fibrillar alignment, occurring naturally in extracellular matrices, is one of the crucial attributes in tissue development. Obtaining fiber alignment in 3D, in vitro remains an important challenge due to non-linear ma...

Gas-phase acylation is an attractive and sustainable method for modifying the surface properties of cellulosics. However, little is known concerning the regioselectivity of the chemistry, i.e., which cellulose hydroxyls are preferentially acylated and if acylation can be restricted to the surface, preserving crystallinities/morphologies. Consequent...

Mixed plastic waste‐streams are a main obstacle to a more extensive implementation of polymer recycling. Separating mixed‐plastic waste streams demands time and effort at collection or in the recycling plant, while many products consist of multiple polymers that cannot be readily separated. Chemical recycling could provide the key to overcome this...

High energy consumption during harvesting is one of the main bottlenecks for sustainable microalgae production. Membranes can efficiently separate microalgae from liquids with low energy consumption, but membrane fouling remains an important issue. Flocculation prior to membrane filtration can increase membrane fluxes and decrease fouling, thus off...

Plastics are produced and used in large quantities worldwide (e.g. as food packaging). In line with this, plastic particles are found throughout the ecosphere and in various foods. As a result, plastics are also present in energy-rich waste biomass derived from the food industry, supermarkets, restaurants, etc. These waste streams are a valuable so...

Covalent functionalization of graphene (CFG) has shown attractive advantages in tuning the electronic, mechanical, optical, and thermal properties of graphene. However, facile, large‐scale, controllable, and highly efficient CFG remains challenging and often involves highly reactive and volatile compounds, requiring complex control of the reaction...

In this paper, a cutter soil mixing residue (CSMR), which is a soil–cement solid waste, was calcined and then used as a partial cement replacement in polyvinyl alcohol fiber reinforced cement composites (PVA-FRCCs). The binder chemistry was characterized using XRD, TGA and FTIR. The fiber–matrix interfacial properties were examined with SEM. The co...

Porous three-dimensional (3D) structures generally improve the performance of electrodes by increasing their active surface area and the diffusion speed of electrolyte ions during charging/discharging. Three-dimensional polypyrrole (PPy) based films were created by electrodepositing PPy in the presence of varying amounts of chloride anions (Cl⁻) an...

This paper reports a multifunctional platform based on a nanocomposite hydrogel combining poly(ethylene glycol), with rhodamine B‐containing silica nanoparticles (RhB@SiO2), as temperature sensors, and gold nanorods (AuNRs) as plasmonic heaters. This composite material acts as a light‐addressable cellular matrix able to induce 3D temperature gradie...

Organic and inorganic acid catalysts enable control over the sol–gel synthesis of crystalline TiO2 nanoparticles. While the mechanism of organic acids (e.g., acetic acid) and inorganic acids (e.g., nitric acid) is well documented, the effect of both acid types used simultaneously is still unclear. This work provides more insights into the mechanism...

Gas-phase acylation of cellulose is an attractive method for modifying the surface properties of cellulosics. However, little is known concerning the regioselectivity of the chemistry, in terms of which cellulose positions are preferentially acylated and if acylation can be restricted to the surface, preserving crystallinities/morphologies. Consequ...

Gas-phase acylation of cellulose is an attractive method for modifying the surface properties of cellulosics. However, little is known concerning the regioselectivity of the chemistry, in terms of which cellulose positions are preferentially acylated and if acylation can be restricted to the surface, preserving crystallinities/morphologies. Consequ...

Selective conversion of 5-hydroxymethylfurfural (HMF) to liquid fuels is an important step in the valorization of carbohydrates. Although not paid much attention to in the scientific community, we discovered an enormous impact of the HMF purity on the product selectivity during its hydroconversion in the presence of Ru/C. The presence of dimethyl s...

In this work, we study interactions of five different hemicellulose models, i.e. Galactoglucomannan, O-Acetyl-Galactoglucomannan, Fuco-Galacto-Xyloglucan, 4-O-Methylglucuronoxylan, and 4-O-Methylglucuronoarabinoxylan, and their respective binding strength to cellulose nanocrystals by molecular dynamics simulations. Glucuronoarabinoxylan showed the...

Flocculation is a widely used technology in industry including for wastewater treatment and microalgae harvesting. To increase the sustainability of wastewater treatment, and to avoid contamination of the harvested microalgal biomass, there is a need for bio-based flocculants to replace synthetic polymer flocculants or metal salt coagulants. We dev...