Setting priorities in CNF particle size measurement: What is needed vs. what is feasible

Measuring the size of cellulose nanomaterials can be challenging, especially in case branched and entangled nanofibrils (CNFs). The International Organization for Standardization, Technical Committee 6, Task Group 1—Cellulosic Nanomaterials, is exploring opportunities to develop standard methods measurement CNF particle distribution. This paper presents a summary available measuring techniques, responses from survey on needs companies researchers, outcomes an international workshop nanofibril standardization. Standardization differed among groups, with Japanese mostly requiring measurements product specification production control, other needing safety/regulatory purposes grade definitions patents. Among all companies, average length width percentiles (D(10), D(50), D(90)) were most desired measurands. Workshop participants concurred that defining location(s) at which measure urgent complex question. They also agreed are needed rapid nanoscale. Our recommendation within ISO start work revise definition CNFs sample preparation guidelines. It was recommended further research done reproducibly prepare hierarchical structures characterize them, automated image analysis structures, classification system encompassing multiple ranges micro- nanoscale fully distinguish samples.