Clean Surface Research Articles

Understanding Binding of Quaternary Ammonium Compounds with Cellulose-Based Fibers and Wipes for Renewable and Sustainable Hygiene Options

Cellulose-based fibers are desirable materials for nonwoven wipes for their good absorbency, strength, cleaning, and biodegradable properties. However, quaternary ammonium compounds (QACs), being cationic in nature, show electrostatic interactions with anionic cellulosic fibers, reducing the available QACs to efficiently clean surfaces. This research presents sustainable alternative fibers that show better controlled exhaustion than commercial wipes and textile fibers. Textile and lignocellulosic fibers were prepared, soaked in QAC, and a UV–vis spectrophotometer was used to measure their exhaustion percentages. Factors such as immersion time and concentration of the disinfectant were also investigated, which affect the rate of exhaustion of the disinfectant from the fibers. A higher immersion time resulted in better exhaustion, whereas the total exhaustion decreased with an increase in the initial concentration of the disinfectant. The exhaustion of benzalkonium chloride (BAC) from the commercial wipes was also investigated at different immersion times and BAC concentrations. It was found that the wood and non-wood fibers showed more controlled exhaustion than the textile fibers and commercial wipes, and could be considered an alternative option for renewable and sustainable wipes and hygiene products.

Carbon-Induced Changes in the Morphology and Wetting Behavior of Ionic Liquids on the Mesoscale.

Thin films of ionic liquids (ILs) have gained significant attention due to their unique properties and broad applications. Extensive research has focused on studying the influence of ILs' chemical composition and substrate characteristics on the structure and morphology of IL films at the nano- and mesoscopic scales. This study explores the impact of carbon-coated surfaces on the morphology and wetting behavior of a series of alkylimidazolium-based ILs. Specifically, this work investigates the effect of carbon coating on the morphology and wetting behavior of short-chain ([C2C1im][NTf2] and [C2C1im][OTf]) and long-chain ([C8C1im][NTf2] and [C8C1im][OTf]) ILs deposited on indium tin oxide (ITO), silver (Ag), and gold (Au) substrates. A reproducible vapor deposition methodology was utilized for the deposition process. High-resolution scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy were used to analyze the morphological and structural characteristics of the substrates and obtained IL films. The experimental data revealed that the IL films deposited on carbon-coated Au substrates showed minor changes in their morphology compared to that of the films deposited on clean Au surfaces. However, the presence of carbon coatings on the ITO and Ag surfaces led to significant morphological alterations in the IL films. Specifically, for short-chain ILs, the carbon film surface induced 2D growth of the IL film, followed by subsequent island growth. In contrast, for long-chain ILs deposited on carbon surfaces, layer-by-layer growth occurred without island formation, resulting in highly uniform and coalesced IL films. The extent of morphological changes observed in the IL films was found to be influenced by two crucial factors: the thickness of the carbon film on the substrate surface and the amount of IL deposition.

Dynamic Antimicrobial Poly(disulfide) Coatings Exfoliate Biofilms On Demand Via Triggered Depolymerization.

Bacterial biofilms are notoriously problematic in applications ranging from biomedical implants to ship hulls. Cationic, amphiphilic antibacterial surface coatings delay the onset of biofilm formation by killing microbes on contact, but they lose effectiveness over time due to non-specific binding of biomass and biofilm formation. Harsh treatment methods are required to forcibly expel the biomass and regenerate a clean surface. Here, a simple, dynamically reversible method of polymer surface coating that enables both chemical killing on contact, and on-demand mechanical delamination of surface-bound biofilms, by triggered depolymerization of the underlying antimicrobial coating layer, is developed. Antimicrobial polymer derivatives based on α-lipoic acid (LA) undergo dynamic and reversible polymerization into polydisulfides functionalized with biocidal quaternary ammonium salt groups. These coatings kill >99.9% of Staphylococcus aureus cells, repeatedly for 15 cycles without loss of activity, for moderate microbial challenges (≈105 colony-forming units (CFU) mL-1, 1 h), but they ultimately foul under intense challenges (≈107 CFU mL-1, 5 days). The attached biofilms are then exfoliated from the polymer surface by UV-triggered degradation in an aqueous solution at neutral pH. This work provides a simple strategy for antimicrobial coatings that can kill bacteria on contact for extended timescales, followed by triggered biofilm removal under mild conditions.

Broad Chain-Length Specificity of the Alkane-Forming Enzymes NoCER1A and NoCER3A/B in Nymphaea odorata.

Many terrestrial plants produce large quantities of alkanes for use in epicuticular wax and the pollen coat. However, their carbon chains must be long to be useful as fuel or as a petrochemical feedstock. Here, we focus on Nymphaea odorata, which produces relatively short alkanes in its anthers. We identified orthologs of the Arabidopsis alkane biosynthesis genes AtCER1 and AtCER3 in N. odorata and designated them NoCER1A, NoCER3A and NoCER3B. Expression analysis of NoCER1A and NoCER3A/B in Arabidopsis cer mutants revealed that the N. odorata enzymes cooperated with the Arabidopsis enzymes and that the NoCER1A produced shorter alkanes than AtCER1, regardless of which CER3 protein it interacted with. These results indicate that AtCER1 frequently uses a C30 substrate, whereas NoCER1A, NoCER3A/B and AtCER3 react with a broad range of substrate chain lengths. The incorporation of shorter alkanes disturbed the formation of wax crystals required for water-repellent activity in stems, suggesting that chain-length specificity is important for surface cleaning. Moreover, cultured tobacco cells expressing NoCER1A and NoCER3A/B effectively produced C19-C23 alkanes, indicating that the introduction of the two enzymes is sufficient to produce alkanes. Taken together, our findings suggest that these N. odorata enzymes may be useful for the biological production of alkanes of specific lengths. 3D modeling revealed that CER1s and CER3s share a similar structure that consists of N- and C-terminal domains, in which their predicted active sites are respectively located. We predicted the complex structure of both enzymes and found a cavity that connects their active sites.

An Innovative Sunlight‐Driven Device for Photocatalytic Drugs Degradation: from laboratory‐ to real‐Scale Application. A First Step Toward Vulnerable Communities

AbstractFreshwater represents one of the most precious resources on the planet, so it is fundamental to preserve it. In this work, an innovative sunlight‐driven device composed of bismuth oxybromide (BiOBr) grown on a material derived from natural sources, i.e., Lightweight Expanded Clay Aggregates (LECA), is developed to clean surface waters under natural solar light irradiation. For this purpose, the photodegradation of two non‐steroidal anti‐inflammatory drugs, ibuprofen, and diclofenac, is investigated under varying operative conditions. Laboratory‐ and real‐scale experiments reveal that the fabricated floating BiOBr/LECA photocatalyst fully degrades diclofenac, whereas limited abatement of ibuprofen is observed. Based on the identification of specific transformation products (TPs) during the degradation, this behavior seems to be strongly related to the different structures of the two drugs. In fact, the main TP produced during diclofenac degradation derives from dechlorination and ring condensation: this type of photocatalytic degradation pathway is generally favored over the C─C bonds's cleavage, which is a unique possibility for IBU abatement. Moreover, the potential partial adsorption of these species on the photocatalyst's active sites can cause their deactivation. Finally, reusability tests demonstrate the high stability of the floating composite.

Healthcare-associated infection management in 62 ICUs for patients with congenital heart disease in China: a survey study.

All patients with congenital heart disease (CHD) receive postoperative management in ICUs. Infection prevention and control (IPC) has a significant impact on prognosis. This study provides a preliminary understanding of the fundamental aspects of IPC in ICUs following CHD surgery in China. From September to October 2023, we initiated a survey on healthcare-associated infection (HAI) management in hospitals that perform CHD surgeries independently. The questionnaires were jointly completed by the ICU physicians and IPC personnel. Duplicate or unqualified questionnaires were excluded from the study. The contents of our questionnaires covered hospital and ICU capacity, performance of the infection control department, HAI surveillance, implementation of IPC measures, and antimicrobial stewardship (AMS). Qualified questionnaires were compared according to the volume of annual CHD surgeries performed in different ICUs. Group 1 was defined as volume more than 300 cases and group 2 was defined as volume less than or equal to 300 cases. Sixty-two of the 118 questionnaires were completed, with a response rate of 53%. The CHD surgical volume in 2022 of the 62 hospitals was 36342, accounting for 52% of the annual CHD surgical volume (69672) across the country. The postoperative infection rates obtained from the 15 ICUs varied from 1.3 to 15%, with a median rate of 4.5%. A total of 16 ICUs provided data on drug-resistant bacteria, Klebsiella pneumoniae exhibiting the highest frequency. More than 95% of ICUs have established complete HAI management systems. Information-based HAI surveillance was conducted in 89% of ICUs. Approximately 67% of ICUs stopped prophylactic antibiotics within 48 hours after surgery. In complex cases, carbapenems were administered empirically in 89% of ICUs. Group 1 had an advantage over group 2 in preventing multi-drug-resistant organisms (all instruments should be used alone 100% vs. 86%, P =0.047; cleaning and disinfection of environmental surfaces, 100% vs. 81%, P =0.035; antibiotic consumption control 85% vs. 61%, P =0.044) and in preventing surgical site infections (perioperative blood glucose monitoring, 88% vs. 67%, P =0.048). However, Group 1 did not perform well in preventing catheter-related bloodstream infection (delayed catheter removal due to convenience of laboratory tests, 31% vs. 6%, P =0.021) and catheter-associated urinary tract infection (delayed catheter removal due to muscle relaxant administration, 88% vs. 58%, P =0.022). A relatively complete HAI management system has been established throughout the country in ICUs for CHD patients. Information-based surveillance of HAI needs to be promoted, and actions should be taken to facilitate the implementation of IPC measures and AMS bundles. Training and feedback are critical for implementing IPC measures.

Lateral junctions of transition metal dichalcogenides as ballistic channels for straintronic applications

In the context of advanced nanoelectronics, two-dimensional semiconductors such as transition metal dichalcogenides (TMDs) are gaining considerable interest due to their ultimate thinness, clean surface and high carrier mobility. The engineering prospects offered by those materials are further enlarged by the recent realization of atomically sharp TMD-based lateral junctions, whose electronic properties are governed by strain effects arising from the constituents lattice mismatch. Although most theoretical studies considered only misfit strain, first-principles simulations are employed here to investigate the transport properties under external deformation of a three-terminal device constructed from a MoS2/WSe2/MoS2 junction. Large modulation of the current is reported owing to the change in band offset, illustrating the importance of strain on the p–n junction characteristics. The device operation is demonstrated for both local and global deformations, even for ultra-short channels, suggesting potential applications for ultra-thin body straintronics.

Exploring how YouTube videos demonstrating preparation of dried wood ear mushrooms could pose food safety risks: a case study

PurposeIn 2020, an outbreak of Salmonella Stanley linked to imported dried wood ear mushrooms affected 55 individuals in the United States of America. These mushrooms, commonly used in Asian cuisine, require processing, like rehydration and cutting, before serving. The US Centres for Disease Control and Prevention advise food preparers to use boiling water for rehydration to inactivate vegetative bacterial pathogens. Little is known about how food handlers prepare this ethnic ingredient and which handling procedures could enable Salmonella proliferation.Design/methodology/approachThis study used content analysis to investigate handling practices for dried wood ear mushrooms as demonstrated in YouTube recipe videos and to identify food safety implications during handling of the product. A total of 125 Chinese- and English-language YouTube videos were analysed.FindingsMajor steps in handling procedures were identified, including rehydration, cutting/tearing and blanching. Around 62% of the videos failed to specify the water temperature for rehydration. Only three videos specified a water temperature of 100 °C for rehydrating the mushrooms, and 36% of the videos did not specify the soaking duration. Only one video showed handwashing, cleaning and sanitising of surfaces when handling the dried wood ear mushrooms.Practical implicationsThis study found that most YouTube videos provided vague and inconsistent descriptions of the rehydration procedure, including water temperature and soaking duration. Food preparers were advised to use boiling water for rehydration to inactivate vegetative bacterial pathogens. However, boiling water alone is insufficient to inactivate all bacterial spores. Extended periods of soaking and storage could be of concern for spore germination and bacterial growth. More validation studies need to be conducted to provide guidance on how to safely handle the mushrooms.Originality/valueThis study will make a distinctive contribution to the field of food safety by being the first to investigate the handling procedure of a unique ethnic food ingredient, dried wood ear mushrooms, which has been linked to a previous outbreak and multiple recalls in the United States of America. The valuable data collected from this study can help target food handling education as well as influence future microbial validation study design and risk assessment.

3D scanning in Cultural Heritage: model creation and digital restoration of the tombstone of the bishop Vasilije Petrović (Negosh) in Saint Petersburg

3D laser and optical scanning techniques are widely employed in Cultural Heritage preservation for documenting pieces of different sizes and shapes. However, due to limitations of the methods available today, the results obtained vary according to different characteristics of the object under study. External surfaces showing very smooth features make the capturing process and the posterior processing a more elaborate task, requiring special attention and additional retouching to improve the final 3D model. Tombstones are a typical example of this type of objects, combining both flat external contours and refined outlines. In this work the procedure of creation of the digital model of the tombstone of the bishop Vasilije Petrović (Negosh) is described, a piece of art which combines both technical and historical importance. Post-processing steps required involved different software (Geomagic Design X, ZBrush, Adobe Photoshop) for surface correction and cleaning, details and photorealistic texture improvements and lost material restoration.

A New Method for Monitoring Scattered Stray Light of an Inner-occulted Coronagraph

The scattered stray light of a coronagraph is a type of stray light that is generated by the objective lens as its surface defects are irradiated by sunlight. The defects mainly include dust and blemishes on the lens surface, microroughness of the lens surface, and impurity and inhomogeneity of the glass. Unlike the other types of relatively stable defects introduced when the objective lens is being manufactured, the scattered stray light caused by dusts on the lens surface is difficult to quantify accurately due to the disorder and randomness of the dust accumulation. The contribution of this type of stray light to the overall stray light level is difficult to determine through simulations and experiments. This can result in continuous deterioration of the stray light level of a coronagraph and thus affect the observation capabilities of the instrument. To solve this issue, through analyzing the forming mechanism of scattered stray light and ghost image generated by the inner-occulted coronagraph, we propose a novel method to monitor the scattered stray light from dusts by utilizing different stray light correlation coefficients. In this method, we first simulate and measure the level of stray light from the ghost image of the objective lens, and then determine the flux ratio of scattered light and ghost image on the conjugate plane. Although the flux ratio varies with the accumulation of dusts on the lens surface, it remains constant on the image plane. Therefore, the level of dust scattering light on the image plane can be obtained by using this ratio together with the level of ghost image stray light. The accuracy of this method has been validated in a laboratory by applying the objective lens with numerous surface cleanliness levels.

In Situ Monitoring of Non-Thermal Plasma Cleaning of Surfactant Encapsulated Nanoparticles

Surfactants are widely used in the synthesis of nanoparticles, as they have a remarkable ability to direct their growth to obtain well-defined shapes and sizes. However, their post-synthesis removal is a challenge, and the methods used often result in morphological changes that defeat the purpose of the initial controlled growth. Moreover, after the removal of surfactants, the highly active surfaces of nanomaterials may undergo structural reconstruction by exposure to a different environment. Thus, ex situ characterization after air exposure may not reflect the effect of the cleaning methods. Here, combining X-ray photoelectron spectroscopy, in situ infrared reflection absorption spectroscopy, and environmental transmission electron microscopy measurements with CO probe experiments, we investigated different surfactant-removal methods to produce clean metallic Pt nanoparticles from surfactant-encapsulated ones. It was demonstrated that both ultraviolet-ozone (UV-ozone) treatment and room temperature O2 plasma treatment led to the formation of Pt oxides on the surface after the removal of the surfactant. On the other hand, when H2 was used for plasma treatment, both the Pt0 oxidation state and nanoparticle size distribution were preserved. In addition, H2 plasma treatment can reduce Pt oxides after O2-based treatments, resulting in metallic nanoparticles with clean surfaces. These findings provide a better understanding of the various options for surfactant removal from metal nanoparticles and point toward non-thermal plasmas as the best route if the integrity of the nanoparticle needs to be preserved.

Investigation of airborne nanoparticles emitted during the laser cleaning process of corroded metal surface

Laser surface cleaning is a promising surface-cleaning technique owing to its numerous benefits, including its noncontact behavior, ease of control, high precision, and no secondary waste generation. However, it cannot prevent airborne nanoparticle emissions during the laser cleaning process. Therefore, the effects of laser-cleaning parameters on airborne nanoparticle generation are analyzed to design potential remediation methods. In this study, the nanoparticles released during the laser cleaning of corroded 304L stainless steel surfaces were investigated. Electrical low-pressure impactor analysis and electron microscopy were conducted to determine how laser parameters influenced the size and amount of emitted nanoparticles. Based on these findings, the feasibility of the filtering emitted nanoparticles using high-efficiency particulate air filters was examined.

Advancements in abrasive water-jet treatment for efficient surface cleaning and comprehensive corrosion removal in steel structures

The effects of a newly developed nozzle type, with divergent flow, and abrasive particle size on the surface preparation properties of steel substrate using abrasive water-jet treatment (AWT) were analyzed. The corrosion and chloride removal efficiencies were evaluated by applying this technique to parts of severely corroded steel structures. The evaluation of the surface characteristics of the treated specimens included analysis of the treatment area, maximum erosion depth, surface roughness profile, and residual abrasive material quantity. The corrosion removal efficiency was assessed using surface salinity measurements and SEM-EDX analysis. The experimental results demonstrated that the application of the developed divergent nozzle and smaller abrasive particle sizes in the AWT process resulted in an expanded treatment range and effective prevention of excessive erosion depth and surface roughness. Additionally, ultra-high-pressure water with abrasives completely eliminated corrosion products and chlorides present on both the surface and interiors of the corroded steel surface, achieving a cleanliness level exceeding Sa 3. This process prevented the formation of flash rust on the cleaned surface for up to 24 h and prolonged the time before the reoccurrence of corrosion on the treated surface. To summarize, the AWT with a divergent nozzle and smaller abrasive particles creates the most ideal surface preparation characteristics for subsequent coating and provides higher surface cleanliness suitable for practical engineering applications.

Evaluation of surface pretreatment methods on thin austenitic stainless steel foils for adhesive bonding applications

ABSTRACT Stainless steel is used across all industries, from the chemical or construction sector to household appliances. To produce load bearing joints, a surface treatment of the passive surface of austenitic stainless steel is generally necessary. However, the treatment of thin-walled foil materials inhibits challenges concerning the deformation under thermal loads. This work investigates the effectiveness and mechanisms of different surface treatments on 50 µm thin AISI 316 L steel foil. Basic cleaning, surface finishing with an aluminum oxide abrasive, flame-pyrolytic deposition of silicon dioxide and application of a primer, etching with hydrochloric acid, treatment by atmospheric plasma, ns-pulsed laser surface cleaning, and fs-laser structuring are investigated. The effects of these treatments are analyzed in surface energy investigations by contact angle measurement, roughness measurements, and SEM-EDX. The bonding strength is tested with epoxy adhesives and a methyl methacrylate adhesive under 90° peel load. The failure mechanisms are further investigated by FTIR spectroscopy and SEM-EDX. The results show that the used coating with primer produces the strongest bonds, followed by the fs-laser treatment. In particular, sub-microscopic surface structures induced by fs-laser show promising results. SEM images show a full wetting of the capillary structures, providing the possibility of mechanical interlocking on a sub-microscopic level.

Perovskite Single Crystals with Self‐Cleaning Surface for Efficient Photovoltaics

AbstractMetal halide perovskite single crystals are promising for diverse optoelectronic applications. As a universal issue of solution‐grown perovskite single crystals, surface contamination causes adverse effect on material properties and device performance. Herein, learning from the self‐cleaning effect of lotus leaf, we address the surface contamination issue by introducing an amphiphilic long‐chain organic amine into the perovskite crystal growth solution. Self‐assembly of CTAC provides a hydrophobic crystal surface, inducing spontaneous removal of residual growth solution, which results in clean surface and better optoelectronic properties of perovskite single crystals. An impressive efficiency of 23.4 % is obtained, setting a new record for FAxMA1‐xPbI3 single‐crystal perovskite solar cells (PSCs). Moreover, our strategy also applies to perovskite single crystals with different morphology and composition, which may contribute to improvement of other single‐crystal perovskite optoelectronic devices.

Perovskite Single Crystals with Self-Cleaning Surface for Efficient Photovoltaics.

Metal halide perovskite single crystals are promising for diverse optoelectronic applications. As a universal issue of solution-grown perovskite single crystals, surface contamination causes adverse effect on material properties and device performance. Herein, learning from the self-cleaning effect of lotus leaf, we address the surface contamination issue by introducing an amphiphilic long-chain organic amine into the perovskite crystal growth solution. Self-assembly of CTAC provides a hydrophobic crystal surface, inducing spontaneous removal of residual growth solution, which results in clean surface and better optoelectronic properties of perovskite single crystals. An impressive efficiency of 23.4 % is obtained, setting a new record for FAx MA1-x PbI3 single-crystal perovskite solar cells (PSCs). Moreover, our strategy also applies to perovskite single crystals with different morphology and composition, which may contribute to improvement of other single-crystal perovskite optoelectronic devices.

Sr4Al2O7: A New Sacrificial Layer with High Water Dissolution Rate for the Synthesis of Freestanding Oxide Membranes.

Freestanding perovskite oxide membranes have drawn great attention recently since they offer exceptional structural tunability and stacking ability, providing new opportunities in fundamental research and potential device applications in silicon-based semiconductor technology. Among different types of sacrificial layers, the (Ca, Sr, Ba)3Al2O6 compounds are most widely used since they can be dissolved in water and prepare high-quality perovskite oxide membranes with clean and sharp surfaces and interfaces; However, the typical transfer process takes a long time (up to hours) in obtaining millimeter-size freestanding membranes, let alone realize wafer-scale samples with high yield. Here, a new member of the SrO-Al2O3 family, Sr4Al2O7 is introduced, and its high dissolution rate, ≈10 times higher than that of Sr3Al2O6 is demonstrated. The high-dissolution-rate of Sr4Al2O7 is most likely related to the more discrete Al-O networks and higher concentration of water-soluble Sr-O species in this compound. This work significantly facilitates the preparation of freestanding membranes and sheds light on the integration of multifunctional perovskite oxides in practical electronic devices.

Rational design and synthesis of triazene-amonafide derivatives as novel potential antitumor agents causing oxidative damage towards DNA through intercalation mode

In this work, we rationally designed and synthesized two novel triazene-amonafide derivatives 2-(2-(diisopropylamino)ethyl)-5-(3,3-dimethyltriaz-1-en-1-yl)-1H-benzo[de]isoquinoline-1,3(2H)-dione (D-11) and 5-(3,3-diethyltriaz-1-en-1-yl)-2-(2-(diisopropylamino)ethyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione (D-12) as potential antitumor agents. The DNA damage induced by the intercalation mode of D-11 (D-12) towards DNA was electrochemically detected through the construction of efficient biosensors. The consecutive processes of reversible redox of naphthylimide ring and irreversible oxidation of triazene moiety were elucidated on the surface of glassy carbon electrode (GCE) by CV, SWV, and DPV methods. Electrochemical biosensors were obtained through the immobilization of ctDNA, G-quadruplexes, poly(dG), and poly(dA), respectively, on the clean surface of GCE. After the incubation of biosensors with D-11 or D-12, the peaks of dGuo and dAdo decreased prominently, and the peak of 8-oxoGua appeared at +0.50 V, suggesting that the interaction between D-11 (D-12) and DNA could result in the oxidative damage of guanine. Unexpected, the as-prepared DNA biosensor possessed satisfactory anti-interference property and good practicability in real samples. UV–vis and fluorescence spectra, and gel electrophoresis assays were employed to further confirm the intercalation mode of D-11 (D-12) towards DNA base pairs. Moreover, D-11 was proved to exhibit stronger anti-proliferation activity than mitionafide and amonafide against both A549 and HeLa cell lines.

Towards quantification of doping in gallium arsenide nanostructures by low-energy scanning electron microscopy and conductive atomic force microscopy.

We calculate a universal shift in work function of 59.4 meV per decade of dopant concentration change that applies to all doped semiconductors and from this use Monte Carlo simulations to simulate the resulting change in secondary electron yield for doped GaAs. We then compare experimental images of doped GaAs layers from scanning electron microscopy and conductive atomic force microscopy. Kelvin probe force microscopy allows to directly measure and map local work function changes, but values measured are often smaller, typically only around half, of what theory predicts for perfectly clean surfaces.

Assessment of Factories on Adherence to COVID-19 Standard Operating Procedures: A Case Study of Wakiso, Mukono, Buikwe, and Jinja Districts, Uganda.

Coronavirus disease (COVID-19) is an infectious disease caused by the SARS-CoV-2 virus. Uganda confirmed the first case of COVID-19 on 21st March, 2020, which led to the first total lockdown in the country. During the lockdown, some factories remained operational; hence, there is a need for a study aimed at assessing the level of adherence to COVID-19 standard operating procedures (SOPs) in factories as a mitigator for the pandemic. A cross-sectional study to assess compliance of factories to COVID-19 SOPs was conducted in Wakiso, Mukono, Buikwe, and Jinja districts during the month of September, 2021. This involved visitation of factories and collection of data using the KoboCollect tool by interviewing general managers as well as human resource managers of the factories. A total of 39 factories were included in the study and were categorized into four major groups; food and beverages (15), plastics (5), construction (8), and others (11). Data analysis was done using STATA version 14.2. Overall adherence to COVID-19 SOPs by the factories was 64.1% (95% CI = 49.1-79.1). Communication and training of employees (79.5%; 95% CI = 66.8-92.2), wearing personal protective equipment (PPE), and respiratory protection (79.5%; 95% CI = 66.8-92.2) as well as enhanced cleaning and disinfection of surfaces (74.4%; 95% CI = 60.6-88.1) were the most implemented SOPs in the factories. Implementation of the SOPs was the highest in Mukono district (88.9%; 95% CI = 68.4-100) and the least in Wakiso district (40.0%; 95% CI = 9.6-70.4). The COVID-19 SOPs were followed mostly in construction material factories (87.5%; 95% CI = 64.6-100) and least in food and beverage factories (40%; 95% CI = 15.2-64.8). There was no significant difference in the adherence of COVID-19 SOPs among the districts (X2 = 5.02 and P=0.17) and factories (X2 = 7.04 and P=0.07). Although good overall adherence to SOPs noted was not dependent on location and type of factory, adherence to some SOPs such as exposure control plan, presence of signages on COVID-19, maintenance of social distance, and implementation of a health control plan varied with location of the district. Likewise, exposure control plan, signages on COVID-19, and maintenance of social distance varied significantly with the type of factory. This study revealed moderately good overall adherence to COVID-19 SOPs by factories, with variations in the level of implementation of individual SOPs being observed.